# Agni and digestion

> Canonical version of this page: https://nighantu.ageayurveda.com/concept/agni-and-digestion/

## How much weight this concept bears

Agni rests almost entirely on classical exegesis. It is a functional postulate with no established physical referent: no enzyme, hormone, transit-time measure, microbiome signature, resting metabolic rate or imaging finding has been shown to correspond to it. No study located here tests an agni instrument against a pre-specified, independently established physiological criterion. The closest thing to such an attempt is the serum-lipid comparison in the 2017 agnibala instrument paper (PMID 27381899), and its own abstract frames the lipids not as a validating criterion but as an after-the-fact check, run once "the statistical validity and reliability" had already been confirmed, on "the practical utility of the newly developed tool"; the result, that "the lipid parameters vary significantly according to the status of Agni" in 300 volunteers aged 18-40, is a cross-sectional association with no reported adjustment for diet or BMI. An earlier version of this section said both that no study even attempts a biological criterion and that the lipid result was the strongest single result; those two statements cannot both stand, and the first has been narrowed to what is defensible. What modern literature exists is dominated by two genres. The first is narrative reviews that restate the thirteen-agni scheme in the vocabulary of enzymes, free radicals or mitochondria, propose a correlate as future work, and stop (PMID 22131747, PMID 22556911 are representative). The second is questionnaire development: at least four separate self-report instruments exist (PMID 26283805, PMID 27381899, PMID 41774580, plus the JAQ used in PMID 35101333), none validated against any external criterion, most validated only by Cronbach's alpha, none reporting test-retest reliability in the papers located here, and no two agreeing on item content. That the field is now commissioning a COSMIN and QUADAS-2 systematic review of these instruments (PMID 42314162) is itself an admission that their psychometric standing is unknown. There is exactly one chance-corrected reliability measurement bearing on agni, and it is unfavourable: four Ayurvedic experts assessing the same 30 knee osteoarthritis patients reached kappa between 0 and 0.4 for central diagnostic aspects including prakriti and agni, despite 95 percent consensus agreement on the final diagnosis (PMID 30653338). Treatment studies for agnimandya (PMID 28827955, PMID 29491670) are small, open-label and scored on the same symptom lists used to make the diagnosis, which makes them close to circular. The honest summary is that agni is an elaborate and long-sustained classical model of digestion and tissue metabolism which is not internally consistent. Sushruta identifies agni with pitta outright while Charaka runs a three-tier jatharagni, bhutagni and dhatvagni architecture (contested #1); the number of agnis is unsettled and the familiar thirteen has no scriptural locus (contested #2); the four states are presented by Charaka's Vimana 6 as four kinds of person and by Sushruta's Sutrasthana 35, and by Charaka's own Chikitsasthana 15/70, as three derangements plus one normal state (contested #5); and samagni is defined behaviourally by Charaka and by output by Sushruta, criteria that select different people (contested #6). The earlier description of the model as "coherent and internally consistent" was a concessive this record's own contested section refutes, and it has been withdrawn rather than the contested material trimmed to fit it. Clinical use rests on symptom-pattern recognition; trained experts do not reliably agree on it; and it has not been operationalized in a way that would let an outside observer confirm or refute it.

Agni is the Ayurvedic name for the transformative capacity held to be responsible for digestion and for tissue-level metabolism. The classical claim is that food does not nourish the body directly: it must first be "cooked" by agni into rasa (a nutrient essence) and kitta (waste), and that the period of life, complexion, strength, ojas and the life-breaths all depend causally on this capacity (Charaka Chikitsasthana 15, Kaviratna's Lesson XV verses 2-3, quoted below). Charaka's Chikitsasthana 15 treats agni as the root of health, disease and death, and the tradition distributes it across a central digestive fire in the gut (jatharagni), five elemental fires (bhutagni) and seven tissue-level fires (dhatvagni). The total of thirteen is a textbook figure and not a scriptural one: Charaka enumerates the five and the seven separately and nowhere states a total, so the summary carries the hedge rather than leaving it to the contested block (see contested #2 and the Ci.15 verses 12-14 entry). A parallel classification describes four functional states of the digestive fire: balanced (sama), irregular (vishama), intense (tikshna) and weak (manda), the last being agnimandya. Whether those four are four kinds of person or three derangements of one person's fire plus one normal state is disputed inside the classical corpus itself, and so is the definition of the balanced state (contested #5, #6). The familiar maxim that weak agni is the etiological starting point of most disease is a teaching commonplace whose usual locus, Ashtanga Hridaya Nidana 12, has not been verified against a primary text in this project; it is therefore not asserted here, and the narrower claim the quoted text does support is that jatharagni is the root of the other fires and that they rise and fall with it (Ci.15, Kaviratna's verse 38). Agni is a functional postulate, not an organ or a substance: Sushruta's own metrical text calls it "invisible owing to its extremely subtle essence", and the classical texts do not locate it in anything measurable beyond its effects on appetite, digestion, stool and bodily strength. The word "absorption", which an earlier version of this summary used, has been removed: it appears in no quoted verse and is a modern physiological term that does not belong in a statement of the classical claim.

## At a glance

| Field | Value |
| --- | --- |
| Subject area | How the body is held to work |
| Domain, as recorded | physiology |
| Contested questions | 7 |
| Stated as not known | 13 |
| Classical citations | 14, 12 quoting the text |
| Research papers assessed | 14 |
| Citations checked | 2026-10-08 |

## What is contested, and by whom

These are the questions on which the sources genuinely disagree. Each position is given as
its source states it. No position is presented as the settled answer, because none of them is.

### Is agni identical with pitta, or distinct from it?

This is contested.

- Sushruta states the identity flatly: pitta is the same as fire, there is no other fire in the organism than pitta, and pitta in its digestive seat is therefore called pachakagni (Su.Su.21).
- Charaka's usage keeps agni as a functional agent distinct from pitta as a dosha, and treats agni disorder and pitta disorder as separately manageable; commentators harmonize the two by making agni the functional aspect of pachaka pitta.
- Modern Ayurvedic physiology literature acknowledges the tension openly: PMID 22131747 states that although the classics give examples equating them, 'some doubt arises behind this concept, that Pitta is Agni'. No resolution is offered.

### How many agnis are there?

This is contested.

- The standard textbook figure is thirteen: one jatharagni, five bhutagni, seven dhatvagni.
- Charaka Ci.15 as translated by Kaviratna enumerates the five and the seven separately and never states a total, so thirteen is a later systematization rather than a scriptural number.
- PMID 22131747 records a third position from within the tradition: agni is in principle innumerable, present in every paramanu of the body, and the enumeration varies across classical texts.

### Do the four agni states map onto the doshas in the conventional way?

This is contested.

- Classical doctrine and most teaching material assign vishamagni to vata, tikshnagni to pitta and mandagni to kapha.
- The one empirical study that tested this (PMID 35101333) found instead that vata-pitta individuals had tikshnagni, vata-kapha had mandagni and kapha-pitta had vishamagni, and reported this as a positive finding without addressing the mismatch with the dvandvaja-to-single-dosha translation it implies.

### Are the four agni states discrete types or points on a continuum?

This is contested.

- Charaka Ci.15/70 treats them categorically: three of the four are by definition grahani-faults, i.e. disease states.
- The instrument literature treats them as four scored subscales that a single person can load on simultaneously (PMID 41774580 reports four correlated subscales, with the samagni subscale the least internally consistent), which is closer to a dimensional than a categorical model. Neither literature addresses the conflict.

### Are the four agni states four kinds of person, or three derangements of one person's fire plus one normal state?

This is contested.

- Four kinds of person. Charaka Vimanasthana 6 closes its list of the four with Kaviratna's aphorism 14: "These are the four different kinds of fire of four different kinds of persons." The same aphorism describes the keen fire in purely positive terms, as the one "which can bear all kinds of dietary riotousness", with no suggestion that it is a disorder.
- Three derangements plus one normal state. Sushruta Sutrasthana 35: "One of these kinds is due to it not being in any way affected by the deranged humours of the body, while the other three are respectively ascribed to the fact of their becoming so deranged." Sushruta also prescribes treatment for the keen fire once it becomes atyagni, which Charaka's Vimana 6 description does not contemplate.
- Charaka takes Sushruta's side against his own Vimana 6 wording. Chikitsasthana 15, Kaviratna's verse 70, quoted in the classical block: "Excepting that fire which is called 'Sama,' the three others, (viz., 'Vishama,' 'Tikshna,' and 'Manda'), are, the Rishis say, called 'Grahani-faults.'" So the disagreement is not only between the two texts but inside Charaka, and this record previously quoted only this side of it.
- The modern instrument literature presupposes the derangement reading without arguing for it, by scoring all four as subscales of a single person (PMID 41774580). None of the secondary sources located here states that the dispute exists.

### How is samagni, the balanced state, actually defined?

This is contested.

- Behaviourally, by response to dietary provocation. Charaka Vimanasthana 6, Kaviratna's aphorism 14: "That fire is said to be even which becomes vitiated by dietary riotousness, but which exists without being deranged when no dietary riotousness is indulged in." On this criterion samagni is a fire that does misbehave, when provoked.
- By output, by complete and timely digestion. Sushruta Sutrasthana 35: "The digestive heat, which fully digests the ingested food at the proper time without the least irregularity, thus reflecting the continuance of the bodily humours in their normal state, is called Samagni." On this criterion samagni is a fire that does not misbehave.
- The two criteria select different people and nothing located here reconciles them. Charaka Vimana 6 adds a third handle in the next aphorism, aphorism 15, which is constitutional rather than either behavioural or output-based: "of those persons that are of equable wind, bile, and phlegm, and that are in their normal state, the (digestive) fires are even."
- The ambiguity shows up in the measurements. The one instrument that scores samagni as its own subscale found it the least internally consistent of the four, with subscale alphas between 0.57 and 0.83 and, in the authors' words, "all subscales except Samagni meeting conventional reliability thresholds" (PMID 41774580).

### Is an agni state a stable trait of the person, or a condition that comes and goes?

This is contested.

- Trait. Charaka Vimanasthana 6, Kaviratna's aphorisms 14 and 15, speaks of "four different kinds of fire of four different kinds of persons" and ties the even fire to persons "of equable wind, bile, and phlegm, and that are in their normal state". A kind of person is not a passing condition.
- State. The same author's grahani chapter makes the fire's condition a consequence of recent conduct. Charaka Chikitsasthana 15, Kaviratna's verses 41-43, quoted in the classical block: "From abstention from all food, from eating food that is indigestible, from eating to excess ... from suppression of the urgings (of nature), the (digestive) fire is vitiated." Every item on that list is something the person did.
- The modern literature does not settle it and at present cannot: no test-retest reliability has been published for any agni instrument in the papers located here, so there is no measurement of how much one person's score moves over time. One cross-sectional survey reports that 61.7 percent of rotating-shift workers had a change in agni status, shifting toward vishamagni on night shifts (PMID 42519781), but both the change and its cause are self-reported.

## What is not known

Stated rather than left out. Where a negative has actually been searched for rather than
assumed, the entry says so.

- Whether agni has any physical correlate at all. Gastric acid output, pancreatic and brush-border enzyme activity, gastric emptying and orocaecal transit time, bile flow, resting metabolic rate, mitochondrial function and gut microbial composition have all been proposed in review articles as candidates. For the microbiome candidate the negative is now a searched one rather than an asserted one: PubMed queries run on 2026-10-06, "prakriti AND microbiome" (9 records), "jatharagni AND microbiome" (0 records) and "ayurveda AND (agni OR jatharagni) AND (gut microbiota OR microbiome)", returned constitution-stratified microbiome work (PMID 29487572, PMID 34148877, PMID 32718805, PMID 31719221, PMID 37655174) in which the stratifier is prakriti and no agni assessment is taken, and no study in which an agni assessment was either the exposure or the outcome. That is a bounded search of one database under those terms on that date, and it cannot support a claim that no such study exists. The other candidate correlates have had no equivalent search documented here, so for those the gap is simply unexamined.
- Whether the four states are stable traits, states that fluctuate day to day, or artefacts of the questionnaire. No test-retest reliability has been published for any agni instrument.
- Whether two trained examiners assessing the same patient would assign the same agni state, and under what conditions. One chance-corrected measurement exists and is unfavourable: in 30 knee osteoarthritis patients assessed in sequence by 4 Ayurvedic experts, kappa for central diagnostic aspects including agni fell between 0 and 0.4 while raw consensus agreement on the final diagnosis was 95 percent (PMID 30653338). What is not known is whether agreement is any better in other conditions, at other centres, with other raters, or when a structured instrument is used instead of clinical judgement, since that study rated expert assessment and not any published agni questionnaire. The claim this record previously carried in this slot, that no interrater reliability figure exists for agni, was false, contradicted eleven other records in this project, and has been withdrawn.
- Whether agni assessment adds anything predictive beyond a general gastrointestinal symptom score. No study has compared an agni instrument against, for example, a validated dyspepsia or GIQLI score to test discriminant validity.
- Whether the dhatvagni and bhutagni tiers correspond to anything at all. All instrument work measures jatharagni only; the seven tissue fires and five elemental fires have never been operationalized.
- Whether agni state at baseline predicts any clinical outcome prospectively. Every study located is cross-sectional or a short uncontrolled intervention.
- How the three-phase avasthapaka model (sweet, sour, pungent phases generating kapha, pitta and vata in turn) relates to measured gastric and intestinal pH and secretion profiles. The correspondence is asserted in reviews and has not been measured.
- Whether the therapeutic categories built on the concept, deepana (kindling) and pachana (digesting), act through any agni-specific mechanism or simply through known prokinetic, carminative and bitter-stimulant pharmacology of the herbs involved.
- Whether the fourfold scheme is pan-classical. The critic finding asserted that Sharngadhara Samhita Purva Khanda 7.26 omits sama and adds bhasmaka. That could not be verified. No public-domain English Sharngadhara translation was located, and searching secondary sources on 2026-10-06 returned the standard four states, sama, vishama, tikshna and manda, attributed to Sharngadhara, rather than the substitution the finding describes. The claim is therefore recorded as unchecked, Sharngadhara is cited nowhere in this record, and the question of which classical and post-classical texts carry which enumeration of the states remains open.
- Where Vagbhata states the four agni states. An earlier pass on this cluster cited Ashtanga Hridaya Sutrasthana 1/8 for them; this pass cites nothing for them. Su.1 and Su.13 are not the same passage, no public-domain English translation of Ashtanga Hridaya exists, and the conflict was not resolvable against a quotable text here. The record therefore makes no claim about where Vagbhata states the four states, and the Ashtanga Hridaya entry below is cited only for the ama and weak-agni account at Su.13, where it is recorded as located and not quoted.
- The locus of the maxim that weak agni is the starting point of most disease. It is usually attributed to Ashtanga Hridaya Nidana 12. It was recorded as unverifiable against a primary text in the previous pass and was not verified in this one, and no public-domain English Ashtanga Hridaya translation exists to quote from. The maxim has accordingly been removed from the summary, and it must not be cited as a locus until checked against a primary text.
- How agni maps onto standardized terminology, and whether the four states map onto anything codeable. The comparator material exists in this project's agni term record: WHO International Standard Terminologies on Ayurveda (2022) renders agni at ITA-2.6.1 as "Digestive, metabolic factors", deliberately avoiding "fire", and treats kayagni as a separate headword at ITA-2.6.2, while NAMASTE / National AYUSH Morbidity Codes carry no standalone code for agni and admit it only as the disorder heading "derangement of digestive power" (agnivaishamyam). What is not known is whether any of sama, vishama, tikshna or manda maps onto a NAMASTE or ICD-11 TM2 category, and that comparator work was flagged in the previous pass as something to gather before drafting and has still not been done. The WHO ISTA licence, CC BY-NC-SA 3.0 IGO, also remains unsettled for publication.
- What the post-classical nibandha layer says about agnimandya. This record covers Charaka and Sushruta only. Madhava Nidana chapter 6 (Grahani Nidana), Bhavaprakasha Purva Khanda on agnimandya, and Yogaratnakara's amavata nidana were all named as gaps and are cited nowhere here, because no public-domain English translation of any of the three was located and this project's rule is no quote, no citation. The record therefore does not cover how the agnimandya doctrine was restated in the later compendia, which is the form in which most modern teaching material actually receives it.

## The terms this concept is built from

| Term | What it names |
| --- | --- |
| [Jatharagni](https://nighantu.ageayurveda.com/lexicon/jatharagni/) | The central digestive fire seated in the gut (specifically in the grahani, said in Charaka to sit above the navel); digests ingested food into rasa and waste. Its governance of the other agnis is stated in the text: "all the other heats have the food-cooking heat for their root. Their increase or decrease depends on its increase or decrease" (Ci.15, Kaviratna's verse 38, quoted below). |
| Bhutagni (five) | Five elemental fires (parthiva, apya, taijasa, vayavya, nabhasa) said to act on the corresponding elemental fraction of already-digested food so that each bodily element is nourished by its like. |
| Dhatvagni (seven) | Seven tissue fires, one for each dhatu (rasa, rakta, mamsa, meda, asthi, majja, shukra), each splitting its substrate into a nourishing portion (prasada) and a waste portion (kitta). |
| Samagni | Balanced state, and the state of health. It is included in Sushruta's definition of a healthy person (Su.Su.15, quoted below), but Charaka and Sushruta do not define it by the same criterion: Charaka defines it behaviourally, by response to dietary provocation, Sushruta by output. See contested #6. |
| Vishamagni | Irregular state; digestion sometimes normal, sometimes deranged, without consistent relation to what is eaten. Conventionally attributed to vata. |
| Tikshnagni | Intense state; digests even unsuitable or excessive food, associated with excessive hunger and, if unfed, with consumption of the tissues. Conventionally attributed to pitta. |
| Mandagni | Weak state. Sushruta: it "causes the tardy digestion even of a scanty meal"; Charaka: "The fire that is weak simply scorches the food taken." This is agnimandya. The further, very widely repeated claim that it is the proximate cause of ama and thence of most disease has no verified locus in this record and is not asserted here; see notKnown on the Ashtanga Hridaya Nidana 12 attribution. Conventionally attributed to kapha. |
| Avasthapaka (three stages) | Three sequential phases of gastric digestion described in Charaka Ci.15: an initial sweet phase in the amashaya producing frothy kapha, a sour phase as food half-digests and passes onward producing pitta, and a pungent phase in the pakvashaya producing vata. |
| Grahani | The named seat of the digestive fire, described as a duct above the navel that retains food until digested; its disorder (grahani roga) is the disease chapter in which the whole agni doctrine is set out. |

## The classical passages

Each citation gives its address so a reader can check it in a printed edition, our account
of what it establishes, and the result of reading it against its source.

### Charaka Samhita Chikitsasthana 15 (Grahani-dosha Chikitsita):Kaviratna's Lesson XV, verse 2 (= 15/3 in the modern vulgate numbering used by carakasamhitaonline; Kaviratna merges the two opening aphorisms, so his numbers run one behind for this chapter), checked against the source

> The period of life, complexion, strength, health, exertion, growth, lustre, ojas, energy, animal and other kinds of heat, and the life-breaths, have all been said to have the digestive fire for their cause.

tr. Avinash Chandra Kaviratna (1896-1913), public domain

The foundational claim that lifespan, strength, complexion, ojas and the pranas all depend causally on agni. This is the single most-cited verse for the concept.

Source: https://archive.org/stream/BIUSante_47357/BIUSante_47357_djvu.txt

### Charaka Samhita Chikitsasthana 15:Kaviratna's Lesson XV, verse 3 (= 15/4 vulgate), checked against the source

> When this fire becomes extinguished, a person dies. When it burns within the body, one lives long without ailments of any kind. When it becomes vitiated, one becomes afflicted with disease. For these reasons, this fire is said to be the root (of all).

tr. Avinash Chandra Kaviratna (1896-1913), public domain

Agni as the root of health, disease and death: the text's own justification for treating digestive capacity as the primary axis of pathology.

Source: https://archive.org/stream/BIUSante_47357/BIUSante_47357_djvu.txt

### Charaka Samhita Chikitsasthana 15:Kaviratna's Lesson XV, verses 6-7 (= vulgate Ci.15/7-8), corrected against the source

> Then, in time, the fire, blown upon by the life-breath called 'Samana' blazes forth and digests the food that has been taken, equally and properly. The result of this is the continuation of the period of life. The (digestive) fire, remaining below, cooks (digests) the food in the stomach, converting it into 'Rasa' and refuse, even as (external) fire and water cook grains of rice in a vessel, for purposes of food.

tr. Avinash Chandra Kaviratna (1896-1913), public domain

The mechanism as the text states it: samana vayu fans the fire, which converts food into rasa and kitta. The cooking-pot simile is the text's own explanatory model, not a later gloss.

Source: https://archive.org/stream/BIUSante_47357/BIUSante_47357_djvu.txt

### Charaka Samhita Chikitsasthana 15:Kaviratna's Lesson XV, verses 12-14, checked against the source

> Since the five heats, viz., that appertaining to earth, that to water, that to fire, that to air, and that to ether, digest earth and the other properties, respectively, numbering five, of the food eaten, therefore, the material properties in the body ... are nourished, respectively, by their correlative elements. ... They who sustain the body, viz., the 'dhatus' (i.e., 'Rasa' or juice, blood, flesh, adeps, marrow, bones, and vital seed), are cooked by their seven respective fires.

tr. Avinash Chandra Kaviratna (1896-1913), public domain

The bhutagni (five) and dhatvagni (seven) tiers in Charaka's own words. Note that Charaka here enumerates five and seven separately and does not state a total of thirteen; the figure of thirteen is a later systematization.

Source: https://archive.org/stream/BIUSante_47357/BIUSante_47357_djvu.txt

### Charaka Samhita Vimanasthana 6 (Roganika Vimana):Kaviratna's aphorisms 14-15 (cited in the modern vulgate as Vi.6/12), checked against the source

> In the fires dwelling in the physical system, a fourfold distinction may be made agreeably to difference of strength. It is as follows: Keen, mild, even, and uneven. Amongst these that fire is said to be keen which can bear all kinds of dietary riotousness. That fire which is endued with characteristic of an opposite kind is called mild. That fire is said to be even which becomes vitiated by dietary riotousness, but which exists without being deranged when no dietary riotousness is indulged in. That fire which possesses characteristics that are the reverse of the above, is called uneven. ... Amongst these, of those persons that are of equable wind, bile, and phlegm, and that are in their normal state, the (digestive) fires are even.

tr. Avinash Chandra Kaviratna (1896-1913), public domain

The four functional states (tikshna, manda, sama, vishama) and the classical criterion distinguishing them, which is behaviour under dietary provocation rather than any measured quantity. Also the link of samagni to dosha equilibrium.

Source: https://archive.org/stream/BIUSante_47357/BIUSante_47357_djvu.txt

### Charaka Samhita Chikitsasthana 15:Kaviratna's Lesson XV, verse 70, checked against the source

> In the Division called 'Vimana' and the Lesson called 'Roganika,' four kinds of digestive fire have been mentioned. Excepting that fire which is called 'Sama,' the three others, (viz., 'Vishama,' 'Tikshna,' and 'Manda'), are, the Rishis say, called 'Grahani-faults.'

tr. Avinash Chandra Kaviratna (1896-1913), public domain

Charaka's own cross-reference tying the Vimana 6 four-state scheme to the grahani disease chapter, and the doctrinal position that the three non-balanced states are pathological by definition.

Source: https://archive.org/stream/BIUSante_47357/BIUSante_47357_djvu.txt

### Sushruta Samhita Sutrasthana 21 (Vranaprashna):Unnumbered in Bhishagratna's rendering; the passage on pitta immediately following the discussion of the doshas (commonly cited as Su.Su.21/9-10), checked against the source

> Now it may be asked whether the Pittam is identical with the elemental fire, or is it something other than that? The question may be answered by stating that the Pittam is the same as fire. ... There is no other fire (heat making factor) in the organism than Pittam. ... Hence this Pittam is called the Pachakagni (digestive fire or heat) in an animated organism.

tr. Kunja Lal Bhishagratna (1907-1916), public domain

Sushruta's explicit identification of agni with pitta, which is the strongest classical statement on the agni/pitta question and the anchor for one side of a genuine internal disagreement.

Source: https://en.wikisource.org/wiki/Sushruta_Samhita,_Volume_1/Chapter_21

### Sushruta Samhita Sutrasthana 15:Unnumbered in Bhishagratna's translation, which prints no Sanskrit verse numbers at all. Located by position: the concluding definitional sentence of Sutrasthana Chapter XV, immediately before "An intelligent physician should preserve the state of health in a healthy individual...". The vulgate locus is given variously as Su.Su.15/41 and Su.Su.15/48 depending on edition and is NOT verified here. Do not cite a numbered vulgate locus from this entry.

**Quotation withheld:** nobody has yet read this quotation against its printed source, and an unchecked quotation is not published here. The passage is at https://en.wikisource.org/wiki/Sushruta_Samhita,_Volume_1/Chapter_15

Balanced agni ('uniformly healthy digestion', samagni) written into the classical definition of health alongside dosha, dhatu and mala equilibrium. This is the verse most often invoked to make agni a criterion of health rather than only of digestion.

### Ashtanga Hridaya Sutrasthana 13 (Doshopakramaniya):13/25-27

Vagbhata's compressed statement that weak agni leaves the first dhatu (rasa) unformed and retained in the amashaya, and the alternative account in the following verse that greatly increased and mutually mixed doshas themselves become ama, likened to poison arising in stored kodrava grain. Relevant here because it is where the agni-failure account becomes the standard textbook formulation.

### Charaka Samhita Chikitsasthana 15:Kaviratna's Lesson XV, verses 49-50, checked against the source

> When the digestive fire becomes unequal (as regards its force or energy), it unequally cooks the food taken and produces inequality between the 'dhatus.' If, when its force or energy is great, it does not get sufficient fuel (in the shape of food and drink), it consumes the 'dhatus.' The fire, which is normal, of a person who eats judiciously, equally cooking the food that is eaten, causes harmony of the 'dhatus.' The fire that is weak simply scorches the food taken.

tr. Avinash Chandra Kaviratna (1896-1913), public domain

The stated consequences of each agni state on tissue equilibrium, including the tikshnagni claim that an unfed intense fire consumes the dhatus.

Source: https://archive.org/stream/BIUSante_47357/BIUSante_47357_djvu.txt

### Charaka Samhita Chikitsasthana 15:Kaviratna's Lesson XV, verse 38. The number 38 is printed immediately after this aphorism, following Kaviratna's number-follows-verse convention, between the markers 37 and 39; the nearest preceding chapter header in the OCR is "LESSON XV". Under the chapter's confirmed one-behind offset this corresponds to vulgate Ci.15/39, where the Sanskrit aphorism beginning "annasya pakta sarvesham paktrinam adhipo matah" is printed. That Sanskrit was located through a search index rather than retrieved from an edition page directly, so the vulgate mapping is recorded as located, not verified., checked against the source

> That heat which cooks (digests) the food eaten is the prince of all heats whose function is cooking. Indeed, all the other heats have the food-cooking heat for their root. Their increase or decrease depends on its increase or decrease.

tr. Avinash Chandra Kaviratna (1896-1913), public domain

The sole textual warrant located for the hierarchy claim this record's components section makes, that jatharagni governs the other agnis. It is a claim about dependence and covariation, not about anatomy: the other heats have this one for their root and move with it. Added on revision in response to missing finding 2, which was correct that the components gloss was making this claim with nothing behind it.

Source: https://archive.org/stream/BIUSante_47357/BIUSante_47357_djvu.txt

### Charaka Samhita Chikitsasthana 15:Kaviratna's Lesson XV, verses 41-43 (the OCR prints the range marker as "4i-43", an obvious misread of 41-43, immediately after the aphorism and between the markers 40 and 44). No vulgate equivalent is asserted., checked against the source

> From abstention from all food, from eating food that is indigestible, from eating to excess, from eating food consisting of inharmonious ingredients, from eating food that is not assimilable, or is heavy, or cold, or excessively dry (unoily), or vitiated, from errors in the administration of purgatives, emetics, and oils, from affliction (i.e., weakness, emaciation, &c.,) by diseases, from absence of harmony in respect of place (habitat), time (age), and season, from suppression of the urgings (of nature), the (digestive) fire is vitiated. The vitiated fire cannot digest food that is even light. The food, again, that is not digested, causes acidity and even becomes poison.

tr. Avinash Chandra Kaviratna (1896-1913), public domain

Charaka's own list of what vitiates the fire, set out in the grahani chapter as a list of causes that come upon the person rather than as a constitutional given. Most items are recent conduct or recent treatment: abstention from all food, indigestible food, eating to excess, food of inharmonious ingredients, food that is unassimilable or heavy or cold or excessively dry or vitiated, errors in the administration of purgatives, emetics and oils, affliction by diseases, and suppression of the urgings of nature. One item in the list is not conduct: 'from absence of harmony in respect of place (habitat), time (age), and season', where habitat and season are standing circumstances and age is a constitutional given. This is the 'state' side of the trait-versus-state question in contested #7, with that qualification. It is the same author and the same treatise as the Vimanasthana 6 aphorism that speaks of 'four different kinds of persons' (cited separately at classical[4]), but a different sthana and a different chapter: this passage is Chikitsasthana, Lesson XV, on the diseases of the grahani. The tension in contested #7 therefore runs across two sthanas of one treatise, not within a single chapter. Added on revision in response to thin finding 5.

Source: https://archive.org/stream/BIUSante_47357/BIUSante_47357_djvu.txt

### Sushruta Samhita Sutrasthana 35 (Aturopakramaniya):Unnumbered in Bhishagratna's rendering, which prints no Sanskrit verse numbers at all. Located by Bhishagratna's own prose and section headings: the paragraph beginning "It has been demonstrated before that the food of a man is digested only with the help of the digestive fire or heat (Pachakagni)", followed by his headings "Samagni and Vishamagni", "Tikshnagni" and "Mandagni", printed at pp. 319-320 of the 1907 Volume 1. No vulgate verse number is asserted., checked against the source

> It has been demonstrated before that the food of a man is digested only with the help of the digestive fire or heat (Pachakagni), which may be divided into four different kinds (states). One of these kinds is due to it not being in any way affected by the deranged humours of the body, while the other three are respectively ascribed to the fact of their becoming so deranged. The digestive fire or heat becomes irregular or fitful (Vishamagni) through the action of the deranged Vayu, becomes keen, through the action of the deranged Pitta, and dull or sluggish, through the action of the deranged Kapha. The fourth kind (Sama) continues in a state unaffected by any of the morbid humoural constituents of the body owing to their maintaining the normal equilibrium. ... The digestive heat, which fully digests the ingested food at the proper time without the least irregularity, thus reflecting the continuance of the bodily humours in their normal state, is called Samagni. ... The digestive heat, which helps the digestion of even a heavy meal within an incredibly short space of time, is called "Keen" (Tikshnagni) and which becoming abnormally augmented begets an excessive or voracious appetite (Atyagni), helps a glutton to digest his frequent meals, and produces a parched throat, palate and lips, heat and other discomforts. ... The digestive fire or heat which causes the tardy digestion even of a scanty meal, and produces heaviness of the abdomen and head, cough, difficult breathing, water-brash, nausea, and weariness of the limbs simultaneously with the taking thereof, is called dull or sluggish (Mandagni).

tr. Kunja Lal Bhishagratna (1907-1916), public domain

The text that defines the four agni states, which this record previously did not cite at all. Three things it establishes that no other citation here does. First, Sushruta's dosha mapping is explicit and matches the conventional teaching: vishama from deranged vata, keen from deranged pitta, dull from deranged kapha. Second, Sushruta frames the four as one undisturbed state plus three derangements, not as four kinds of person, which is the other side of contested #5. Third, his samagni is defined by output, "fully digests the ingested food at the proper time", not by behaviour under dietary provocation as in Charaka Vimana 6, which is contested #6. Added on revision in response to missing finding 1.

Source: https://www.wisdomlib.org/hinduism/book/sushruta-samhita-volume-1-general-principles/d/doc122935.html

### Sushruta Samhita Sutrasthana 35 (Aturopakramaniya):Unnumbered in Bhishagratna's rendering. Located by position: the "Metrical Texts" paragraph that closes the agni section of Chapter XXXV, printed at pp. 321-322 of the 1907 Volume 1, immediately before the passage on the three stages of life. This project's agni term record cites the vulgate locus for this passage as Su.Su.35/27; Bhishagratna prints no verse numbers, so that mapping is recorded here as unverified and is not asserted., checked against the source

> The fire, that burns within a person, is godly in its subtle essence, and possesses the divine attributes of atom-like invisibility, weightlessness, etc., and is the digestant of food. It takes up the lymph chyle of different tastes for the purpose of digestion, and is invisible owing to its extremely subtle essence. The three vital Vayus known as Prana, Apana and Samana, located in their own spheres within the organism, feed it and keep it burning.

tr. Kunja Lal Bhishagratna (1907-1916), public domain

The sharpest classical statement against the whole measurement programme, and the reason this record treats agni as a functional postulate rather than a thing with a referent: the text itself says the fire is invisible because of its subtlety. It also gives Sushruta's version of the pranas-feed-the-fire mechanism, naming three vayus where Charaka Ci.15 names samana alone. Added on revision in response to missing finding 1.

Source: https://www.wisdomlib.org/hinduism/book/sushruta-samhita-volume-1-general-principles/d/doc122935.html

## What the research actually shows

Every paper located for this concept, with what it measured and what it does and does not
establish. The assessment is ours.

### Reliability of Ayurvedic Diagnosis for Knee Osteoarthritis Patients: A Nested Diagnostic Study Within a Randomized Controlled Trial.

J Altern Complement Med · 2019 · PMID 30653338 (https://pubmed.ncbi.nlm.nih.gov/30653338/)

The only chance-corrected inter-rater reliability measurement located for agni. A diagnostic reliability study of 30 knee osteoarthritis patients and 4 Ayurvedic experts, nested in a randomised controlled trial, with patients diagnosed in sequence by all four using a semistructured history form after a nominal group consensus procedure had fixed the items to be diagnosed. The abstract reports that high percentages of agreement on main diagnostic entities and the final diagnosis (95% consensus agreement on main diagnosis) "was not reflected in the corresponding kappa values, which largely yielded fair-to-poor inter-rater agreement kappas for central diagnostic aspects such as prakriti and agni (kappa values between 0 and 0.4)", and that agreement on disease-related entities was better than on constitutional entities.

**How much it shows.** Empirical, nested in an RCT, Fleiss' and Cohen's kappa, which is the correct statistic and is rare in this literature. Small and bounded: 30 patients, 4 raters, one condition, and a setting where a prior consensus procedure should have inflated rather than deflated agreement. It measures expert clinical assessment of agni, not any of the published agni questionnaires, so it does not tell us the reliability of those instruments. The gap between 95% raw agreement and kappa under 0.4 is the finding that matters and is the part most often dropped when this study is cited.

### Development, Validation, and Verification of a Self-Assessment Tool to Estimate Agnibala (Digestive Strength).

J Evid Based Complementary Altern Med · 2017 · PMID 27381899 (https://pubmed.ncbi.nlm.nih.gov/27381899/)

Development of a self-assessment questionnaire for agnibala (digestive strength) in 300 healthy volunteers aged 18-40, reporting internal consistency and a statistically significant variation in serum lipid parameters across agni categories. This is the most-cited attempt to tie an agni instrument to any objective measurement.

**How much it shows.** Empirical, but a single-centre instrument-development study with no external gold standard. The lipid association is cross-sectional, not adjusted for diet or BMI in any reported way, and cannot establish that the instrument measures a distinct physiological entity. No test-retest or interrater data. It is the strongest agni paper available, and that is itself informative about the field.

### Formation and validation of questionnaire to assess Jāṭharāgni.

Anc Sci Life · 2015 · PMID 26283805 (https://pubmed.ncbi.nlm.nih.gov/26283805/)

A 64-item Jatharagni Assessment Questionnaire administered to 500 volunteers, validated by Cronbach's alpha alone (overall 0.916; domain alphas 0.873-0.909).

**How much it shows.** Empirical but methodologically thin. Cronbach's alpha measures internal consistency only; it says nothing about whether the construct exists or whether the instrument distinguishes agni states from general gastrointestinal symptom burden. No convergent, discriminant or criterion validity was tested.

### Development and Preliminary Psychometric Evaluation of Agni Assessment Scale: A Measure of Functional Digestive Capacity Based on Ayurveda.

Complement Med Res · 2026 · PMID 41774580 (https://pubmed.ncbi.nlm.nih.gov/41774580/)

The Agni Assessment Scale (CCRAS/IIT Delhi), a 26-item self-report measure developed in 467 Indian participants, with exploratory factor analysis supporting four subscales matching the classical sama/vishama/manda/tikshna scheme. Subscale alphas ranged 0.57-0.83, and the Samagni subscale failed to reach conventional reliability thresholds.

**How much it shows.** The most methodologically careful agni instrument paper to date, and it is candid about its limits. Exploratory factor analysis only, no confirmatory factor analysis, no external criterion, and the subscale for the supposedly normal state was the least reliable of the four. The authors themselves call the evidence preliminary.

### Evaluation of the Psychometric Properties and Applicability of Agni Assessment Tools in Ayurveda: Protocol for a Systematic Review.

JMIR Res Protoc · 2026 · PMID 42314162 (https://pubmed.ncbi.nlm.nih.gov/42314162/)

A registered protocol (PROSPERO CRD42024626327) for a systematic review of the psychometric properties of all existing agni assessment tools, using COSMIN and QUADAS-2. Its existence documents that a plurality of mutually unvalidated agni instruments now exists and that no one has yet appraised them against a common standard.

**How much it shows.** Protocol only. It reports no results. Its value here is as evidence about the state of the field rather than as evidence about agni; the review itself is not expected before late 2026.

### Jatharagni and Prakriti of young Indian adult population: A descriptive cross-sectional study.

J Ayurveda Integr Med · 2022 · PMID 35101333 (https://pubmed.ncbi.nlm.nih.gov/35101333/)

Cross-sectional survey of 18-30 year old students reporting a statistically significant association between prakriti type and jatharagni type, but with the specific pairings Vata-pitta/tikshnagni, Vata-kapha/mandagni and Kapha-pitta/vishamagni.

**How much it shows.** Empirical cross-sectional study, but both variables are self-report questionnaires administered to the same person, so shared method variance is uncontrolled and a significant chi-square is close to inevitable. The pairings it reports do not match the conventional classical mapping (vata/vishama, pitta/tikshna, kapha/manda), which the paper does not reconcile.

### A cross-sectional survey to evaluate the status of digestion in rotating- and fixed-shift workers.

Front Med (Lausanne) · 2026 · PMID 42519781 (https://pubmed.ncbi.nlm.nih.gov/42519781/)

Comparative cross-sectional survey of 350 IT workers using the 2017 agnibala questionnaire, reporting that 61.7% of rotating-shift workers had a change in agni status, with a shift toward vishamagni during night shifts.

**How much it shows.** Convenience sample, self-report instrument, self-reported attribution of the change to shift work. It is consistent with the general finding that circadian disruption worsens gastrointestinal symptoms, but it cannot distinguish 'agni changed' from 'shift workers report more digestive complaints'.

### Physiological aspects of Agni.

Ayu · 2010 · PMID 22131747 (https://pubmed.ncbi.nlm.nih.gov/22131747/)

A widely cited exposition of the thirteen-agni scheme and the prasada/kitta model, explicitly noting that the enumeration of agni varies between classical texts and that the identification of pitta with agni is doubted.

**How much it shows.** Narrative review, no data. Useful as a statement of the doctrine and, unusually, as an acknowledgement from inside the tradition that the count and the pitta-identity are not settled. It proposes enzyme analogies without testing any.

### Overlooked contributions of Ayurveda literature to the history of physiology of digestion and metabolism.

Hist Philos Life Sci · 2023 · PMID 36947245 (https://pubmed.ncbi.nlm.nih.gov/36947245/)

A history-of-science treatment of the Ayurvedic account of digestion (avasthapaka, the multi-level agni scheme) juxtaposed with the Western physiological tradition, arguing the classical descriptions deserve historical recognition while stating plainly that the understanding was 'primitive and insufficient in many ways'.

**How much it shows.** Scholarly narrative review in a mainstream history and philosophy of science journal. Makes a historical claim, not a physiological one, and is careful not to assert modern validity. The most intellectually honest secondary source located for this concept.

### A randomized open-label comparative clinical study of effect of lifestyle modification and Shatapushpadya Churna on Agnimandya.

Ayu · 2016 · PMID 28827955 (https://pubmed.ncbi.nlm.nih.gov/28827955/)

Randomized open-label comparison of lifestyle modification plus placebo against Shatapushpadya churna in 33 patients diagnosed with agnimandya; both arms improved on symptom scores, with the lifestyle arm doing better.

**How much it shows.** Very small, open-label, outcomes are subjective symptom scores derived from the same classical criteria used to make the diagnosis. No objective digestive measure. Cannot separate treatment effect from regression to the mean or expectation.

### Effect of Ekakala Bhojana in patients of Agnimandya.

Ayu · 2016 · PMID 29491670 (https://pubmed.ncbi.nlm.nih.gov/29491670/)

Small randomized comparison in agnimandya patients suggesting once-daily eating (ekakala bhojana) outperformed trikatu tablets on appetite and digestive-capacity scores.

**How much it shows.** Small, open-label, 10-day, subjective endpoints, no objective measure of digestion. Reported percentage improvements without confidence intervals. Hypothesis-generating at best.

### Possible Correlates of Free Radicals and Free Radical Mediated Disorders in Ayurveda with Special Referance to Bhutagni Vyapara and Ama at molecular Level.

Anc Sci Life · 1999 · PMID 22556911 (https://pubmed.ncbi.nlm.nih.gov/22556911/)

An early and explicit instance of the genre this record's evidenceState describes: a proposal to correlate bhutagni function and ama with free radicals and free-radical-mediated disorders at the molecular level. It is cited here only as an exemplar of that genre, which is what the evidenceState uses it for.

**How much it shows.** Narrative, speculative, no data, and nothing in it was subsequently tested as far as this record can show. Published 1999 in Anc Sci Life 19(1-2):17-20. Its value here is documentary.

### Western Indian Rural Gut Microbial Diversity in Extreme Prakriti Endo-Phenotypes Reveals Signature Microbes.

Front Microbiol · 2018 · PMID 29487572 (https://pubmed.ncbi.nlm.nih.gov/29487572/)

16S rRNA gut microbiome profiling in three predominant prakriti groups drawn from a genetically homogenous western Indian rural cohort (CSIR Ayurgenomics / TRISUTRA, with CCRAS-adjacent and KEM Pune collaborators). It reports broadly uniform community composition with specific taxa differentially abundant by prakriti, including gender-specific signature taxa. It is cited here for what it does not do: the stratifying variable is prakriti, not agni, and no agni assessment appears in it, so it does not test the microbiome candidate correlate for agni.

**How much it shows.** Real sequencing data on a defined cohort, and the best-resourced constitution-and-microbiome work located. It cannot bear on agni at all, because agni was not measured. Standing limits of this design apply to its own claim too: 16S rather than shotgun, differential-abundance findings without an independent replication cohort, and prakriti itself assigned by an instrument whose inter-rater reliability is the subject of PMID 30653338 above.

### Exploring the signature gut and oral microbiome in individuals of specific Ayurveda prakriti.

J Biosci · 2021 · PMID 34148877 (https://pubmed.ncbi.nlm.nih.gov/34148877/)

Gut and oral metagenomes from 272 healthy individuals of various predominant prakritis, reporting a shared core microbiome with prakriti-specific signatures such as preferential presence of Paraprevotella and Christensenellaceae in vata individuals. Cited here, like the previous entry, for the boundary of the literature rather than for a positive finding about agni: the stratifier is again prakriti, and agni is not assessed.

**How much it shows.** Larger than the 2018 cohort and adds an oral compartment. Its own weakest step is the one it leans on hardest, comparing each prakriti's core microbes against a database of "healthy" microbes and reading the functional roles back onto Ayurvedic physiological descriptions, which is interpretation rather than test. No agni measurement, so it is silent on this concept.

## Open questions on this record

Recorded rather than resolved.

- Does any Sanskrit edition of Charaka Vimanasthana 6 support reading "four different kinds of fire of four different kinds of persons" as a constitutional claim, or is "of persons" Kaviratna's addition? This is the single question on which contested #5 and #7 turn, and it needs the Sanskrit, not a translation.
- What is the vulgate verse number for the Sushruta Sutrasthana 35 metrical text on the fire's invisibility? This project's agni term record says Su.Su.35/27. Bhishagratna prints no numbers, so it needs a Sanskrit edition to settle.
- Is there any public-domain English translation of Ashtanga Hridaya, Madhava Nidana, Bhavaprakasha or Yogaratnakara? Five gaps in this record close immediately if there is, and stay open if there is not.
- Does the forthcoming COSMIN review of agni instruments (protocol at PMID 42314162) appraise any instrument against an external criterion, or only against each other? If only against each other, the field's central gap will survive its own systematic review.

## Citation

Age Ayurveda Nighantu, "Agni and digestion", https://nighantu.ageayurveda.com/concept/agni-and-digestion/, CC BY 4.0.
Whole concept set: https://nighantu.ageayurveda.com/concepts.json and https://nighantu.ageayurveda.com/concepts.csv.

Educational reference only. This page describes what a body of theory claims and how well it
is evidenced. Nothing here is advice, and nothing here describes how any condition should be
treated.