Ayurveda
BaelAegle marmelos
Ayurveda uses unripe bael fruit for diarrhea. The one human trial combined it with brahmi: 169 IBS patients, 64.9% improved on the formula versus 32.7% on placebo.
- Botanical name
- Aegle marmelos
- Part used
- unripe fruit pulp (leaf and root are also used)
- Also called
- Sanskrit Bilva, Shriphala; Hindi Bel; Bengal quince, Stone apple
- Used in
- Ayurveda
- Taken for
- Loose stools and diarrhea, Indigestion, Cramping and pain
- Sold as
- powder, capsules, syrup, decoction, dried fruit
Bael, the plant and the part used
Bael is a thorny, medium-sized tree of the citrus family (Rutaceae), native to India and grown across the subcontinent. Its fruit has a hard woody shell around a sticky, aromatic pulp. In Ayurveda the unripe fruit is the part used for the gut, usually sliced and dried and then ground to a powder or boiled into a decoction. The leaf (as a fresh juice) and the root are used for other purposes and are sometimes included in gut formulas.
Today bael is sold as dried fruit powder, capsules, syrup and as an ingredient in compound Ayurvedic formulas. Most of what is known about its effects on the gut comes from laboratory and rodent studies of fruit and root extracts; the human trial we could find tested a two-herb formula, not bael alone. A published case report (see Safety) describes a bowel obstruction caused by bael fruit in the rectum.
Traditional uses, in their own terms
Ayurveda (about Ayurveda)
An Ayurvedic college monograph describes the unripe fruit as astringent and bitter in taste (rasa), light and dry in its qualities (guna), heating in potency (virya) and pungent in its after-digestion effect (vipaka). The tradition says it calms vata and kapha, two of its three governing principles (doshas). Its listed actions are grahi, meaning “holding” or binding, used for loose stools, and dipana-pacana, meaning it kindles and aids digestion.
The monograph lists atisara (acute loose stools), grahani (a chronic condition of poor digestion with erratic stools), agnimandya (weak digestive fire) and arsas (piles) as indications. It also cites classical treatments from the Sushruta and Charaka texts, and the Bhavaprakasha Nighantu supplies the synonyms. The unripe fruit is the form the monograph lists for the gut.
Compounds, and what the laboratory says about them
Screening of an aqueous extract of unripe fruit found alkaloids, tannins, saponins, flavonoids, steroids and terpenoids, and the fruit contains carotene, thiamine, riboflavin, niacin and vitamin C. The authors of that work suggest the flavonoids, phenolics and steroids may drive its anti-inflammatory effect but did not isolate an active compound. Two laboratory studies bear on diarrhea. A hot-water decoction of the unripe pulp killed Giardia and rotavirus in the dish, left six bacterial strains unharmed, but reduced bacterial adherence to and invasion of gut-lining cells and affected cholera toxin. A chloroform root extract was active against Vibrio cholerae, E. coli and Shigella among 35 diarrhea-causing strains. These are cell and microbe findings.
Trials in people, with the numbers
The human evidence is one trial from 1989. Yadav and colleagues randomized 169 people with irritable bowel syndrome to three arms for 6 weeks in a double-blind design: standard drugs (clidinium bromide, chlordiazepoxide and isaphaghula husk, 60 patients), a compound Ayurvedic preparation containing Aegle marmelos plus Bacopa monnieri (brahmi, 57 patients), or a matching placebo (52 patients). The authors judged the Ayurvedic preparation effective in 64.9%, standard therapy in 78.3% and placebo in 32.7%. The formula did better than placebo in the diarrhea-predominant form of IBS; standard therapy did better in the painful form; in the gas-predominant form both were similar to placebo. At follow-up beyond 6 months, neither therapy was better than placebo at limiting relapse.
Because the preparation combined bael with brahmi, the trial cannot say what bael contributed. The abstract does not give the dose, and the trial is more than three decades old.
For diarrhea itself we found no human trial of bael. The support is from the laboratory: the decoction and root-extract studies above, a rat study in which the root extract significantly reduced castor-oil-induced diarrhea, and a 2012 rat study in which an aqueous unripe-fruit extract at 150, 200 and 250 mg/kg reduced inflammation in acetic-acid and indomethacin models of bowel inflammation, with the 250 mg/kg dose comparable to prednisolone. Rodent doses do not translate to human doses, and none of this has been repeated in people.
| Study | Dose | What it found |
|---|---|---|
| Double-blind randomized trial, 169 people with IBS, 6 weeks (bael plus brahmi formula, standard drugs, placebo) PMID 2697693 | Not stated in the abstract (compound preparation) | Judged effective in 64.9% (formula, n=57), 78.3% (standard drugs, n=60) and 32.7% (placebo, n=52); formula better than placebo in diarrhea-predominant IBS |
| Rat study of an aqueous unripe-fruit extract in two bowel-inflammation models PMID 23112424 | 150, 200 and 250 mg/kg (rodent doses) | Dose-dependent less intestinal inflammation; 250 mg/kg comparable to prednisolone; no deaths at up to 2,000 mg/kg in the safety test |
| Laboratory study of unripe-fruit decoction against diarrhea-causing organisms PMID 19930633 | Hot-water decoction (in vitro) | Killed Giardia and rotavirus; reduced bacterial adherence and invasion; affected cholera toxin; no effect on six bacterial strains' viability |
| Chloroform root extract tested on 35 diarrhea-causing strains and in rats PMID 16397850 | Extract (in vitro and rat) | Most active against Vibrio cholerae, then E. coli and Shigella; significant effect against castor-oil-induced diarrhea in rats |
The doses on record
The IBS trial’s abstract does not give the dose of its bael-and-brahmi preparation. The rat studies used 150 to 250 mg/kg of unripe-fruit extract, which are animal doses.
Ayurvedic college monographs give traditional amounts for bael of 2 to 4 g of powder, 50 to 100 ml of a decoction and 10 to 15 ml of fresh leaf juice, with the unripe fruit as the main part used.
None of this is a dose recommendation. It is what the literature used, set down so a label can be compared with it; a pharmacist or clinician decides what applies to you.
The safety record
The 1989 abstract reports no adverse-event data. In a safety test following OECD acute-toxicity guideline 423, an unripe-fruit extract at up to 2,000 mg/kg caused no deaths or behavior changes in rats over 14 days; no repeated-dose data were reported. A 2020 case report from a hospital in India describes bowel obstruction in an elderly man caused by bael fruit lodged in the rectum, and its authors point to unregulated use of traditional remedies. We found no pregnancy data.
Binding (grahi) is part of how the tradition describes the unripe fruit, which is why it is mainly listed for loose stools, although the 2012 rat paper also lists constipation among the fruit’s traditional uses. On product quality, a 2008 JAMA study of Ayurvedic medicines ordered online found lead, mercury or arsenic in 20.7% of 193 products, with higher rates in mineral-and-metal preparations; that finding is about those medicines, and bael fruit powder was not analyzed separately.
Medicines it can interact with
We found no human interaction study of bael. The 1989 IBS trial used standard drugs and the formula in separate arms and did not test combining them. The 2012 rat work compared the fruit extract with prednisolone but did not examine how the two act together. Interaction questions for bael are therefore open rather than answered in either direction.
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The questions that come up
Has bael been tested for diarrhea in people?
We could not find a human trial of bael for diarrhea. The human evidence is a 1989 trial of a bael-and-brahmi formula in irritable bowel syndrome, and the diarrhea work on bael alone is laboratory and rodent research.
What did the irritable bowel trial find?
Among 169 people over 6 weeks, the formula was judged effective in 64.9% (57 people), standard drugs in 78.3% (60 people) and placebo in 32.7% (52 people). The formula’s advantage over placebo was in the diarrhea-predominant form, and no treatment beat placebo at limiting relapse after 6 months.
Why does Ayurveda use the unripe fruit?
College monographs describe the unripe fruit as astringent and binding (grahi), qualities the tradition ties to loose stools. These are the tradition’s statements, not trial results.
What does the case report about bowel obstruction mean?
It describes one elderly man whose bowel was blocked by bael fruit in the rectum. It is a single case, and its authors raise it as a reason for caution about unregulated use of traditional remedies.
Is bael the same as the bilva in Ayurvedic formulas?
Yes. Bilva is the Sanskrit name for Aegle marmelos, and Bel is the Hindi name. Formula labels may use any of the three.
Sources
- Yadav SK, Jain AK, Tripathi SN, Gupta JP, "Irritable bowel syndrome: therapeutic evaluation of indigenous drugs", Indian J Med Res 1989;90:496-503 pubmed.ncbi.nlm.nih.gov/2697693
- Behera JP et al., "Effect of aqueous extract of Aegle marmelos unripe fruit on inflammatory bowel disease", Indian J Pharmacol 2012;44(5):614-618 pubmed.ncbi.nlm.nih.gov/23112424
- Brijesh S et al., "Studies on the antidiarrhoeal activity of Aegle marmelos unripe fruit: validating its traditional usage", BMC Complement Altern Med 2009;9:47 pubmed.ncbi.nlm.nih.gov/19930633
- Mazumder R et al., "Antidiarrhoeal evaluation of Aegle Marmelos (Correa) Linn. root extract", Phytother Res 2006;20(1):82-84 pubmed.ncbi.nlm.nih.gov/16397850
- Singh MP et al., "A bael (Aegle marmelos) in rectum presenting with bowel obstruction in an elderly man", J Surg Case Rep 2020;2020(3):rjaa043 pubmed.ncbi.nlm.nih.gov/32161641
- Shri Dhanwantry Ayurvedic College & Hospital, Chandigarh, Dravyaguna monograph: Bilva www.sdach.ac.in/about-dravyaguna-vigyan/dravyaguna-vigyan-blogs/bilva
- Saper RB et al., "Lead, mercury, and arsenic in US- and Indian-manufactured Ayurvedic medicines sold via the Internet", JAMA 2008;300(8):915-923 pubmed.ncbi.nlm.nih.gov/18728265