Bilva (Bael): Traditional Use, Evidence & Safety

TL;DR

Bilva is the fruit pulp of Aegle marmelos, in the Ayurvedic Pharmacopoeia and traditionally used for diarrhea and dysentery. A 1989 double-blind trial (n=169) of a bael-containing compound beat placebo for diarrhea-predominant IBS; a 226-patient crossover poster found bael extract alone reduced stool frequency and loose stools in IBS-D. The 1993 unripe-fruit trial is review-summary only; colitis evidence is animal-only.

What it is

Bilva is the dried fruit pulp of Aegle marmelos (L.) Corrêa, family Rutaceae: bael in Hindi, bilwa in Sanskrit. The tree is indigenous to the hills and plains of the Indian subcontinent and Southeast Asia, and the fruits are woody-skinned, 5–15 cm across, with an aromatic pulp (Pharmacognosy Magazine article). The Ayurvedic Pharmacopoeia of India (Part I, Volume I) monographs it as "Bilva (Frt. Pulp)", i.e. fruit pulp. That is a bibliographic reference; I could not locate an official online edition of the monograph.

Traditional use

In Ayurveda, the bael fruit is described as useful for gastrointestinal disorders on account of its astringent, digestive, and stomachic properties. That phrasing comes from a modern pharmacology paper summarizing the tradition (Phytomedicine 2025). It "has been used in traditional medicinal practice for the treatment of diarrhea since ancient times," with the unripe or half-ripe fruit valued for chronic diarrhea and dysentery (Pharmacognosy Magazine article). Traditional claims, not clinical proof. The human-trial evidence gets its own section below.

What modern research says

The verifiable human record has two entries. The only randomized trial of a bael extract on its own is the crossover poster below; an older trial tested bael inside a compound preparation.

IBS with diarrhea (randomized crossover trial)

The only randomized trial of a bael-fruit extract on its own that I could verify is a prospective, double-blind crossover trial by gastroenterologists at BJ Medical College and Sassoon Hospitals, Pune (Thorat et al.), presented as a UEG Week e-poster, not a journal paper. Here is the design, because the details matter: 226 patients with diarrhea-predominant irritable bowel syndrome (IBS-D) and a normal colonoscopy were randomized to a dried powdered extract of Aegle marmelos fruit (300 mg daily in three divided doses) or a matched placebo for two weeks, after a two-week run-in. Then they crossed over to the other arm for two further weeks. After adjusting for baseline stool frequency, the bael extract produced a statistically significant reduction in both stool frequency and the number of loose stools, with the change visible at crossover in both directions. No significant change in bloating or incomplete evacuation. No significant side effects noted (UEG Week e-poster).

Two caveats, and I will not soften them. This was a conference poster, not a peer-reviewed publication. And it is a single trial. Replication in a published, peer-reviewed trial is still needed before anyone treats this as settled. A companion article on Bilva Majja (bilva-majja) notes an older 1993 human trial of powdered unripe bael fruit for diarrhoea, available only as a review summary. I could not verify the primary paper, so it is not counted here.

IBS: the 1989 BHU compound trial

In 1989, physicians at the Institute of Medical Sciences, Banaras Hindu University (Departments of Medicine and Kayachikitsa) published a double-blind randomized trial of 169 IBS patients treated for six weeks with an Ayurvedic compound of Aegle marmelos plus Bacopa monnieri, against standard therapy and placebo. The Ayurvedic arm was effective in 64.9% of patients, behind standard therapy at 78.3% but well ahead of placebo at 32.7%, and the authors noted it was "particularly beneficial in diarrhoea predominant form as compared to placebo." Two limits travel with the result: bael was not tested alone, so its individual contribution is unknown; and at follow-up beyond six months, neither active arm beat placebo at preventing relapse (Yadav SK et al., via the POPLINE archive).

Ulcerative colitis (animal studies only)

I found no human trials of bilva for ulcerative colitis. The animal work, though, is more developed than for most herbs on this site. In rats, an aqueous extract of unripe bael fruit significantly improved disease-activity, macroscopic, and microscopic scores in both acetic acid–induced ulcerative colitis and indomethacin-induced enterocolitis models (Indian J Pharmacol, PMC). A 50% ethanolic extract of dried fruit pulp (200 mg/kg for 14 days) showed curative effects against TNBS-induced colitis in rats, described as comparable to sulfasalazine 100 mg/kg (Ghatule et al., Pharmacognosy Magazine). And a 2025 mouse study found an aqueous fruit extract (300 mg/kg) ameliorated DSS-induced colitis, partly through gut-microbiota shifts and intestinal-barrier protection, and reported the extract safe up to 3000 mg/kg in that animal work (Phytomedicine 2025). All of it animal work. It cannot be read as evidence that bael treats colitis in people.

What the evidence does not support (yet)

There is no human evidence for bilva in ulcerative colitis, Crohn's disease, or general "gut detox" claims. The verifiable human data begin and end with the two IBS entries above: one compound trial from 1989, one single-arm-extract crossover poster. That is the whole file.

Dosage

There is no established dose for bilva. The regimen used in the IBS-D trial was 300 mg/day of dried powdered fruit extract in three divided doses: a research regimen from one unpublished conference trial, not a personal recommendation (UEG Week e-poster).

Safety & contraindications

In the two-week crossover trial, no significant side effects were reported. Read that again: two weeks of exposure, one trial. That is not a safety profile. Longer-term human safety data for bilva fruit extract were not identified in the reviewed sources. Anyone with inflammatory bowel disease should not use bael as a substitute for prescribed treatment. Discuss it with a gastroenterologist first.

FAQs

What is bilva?

Bilva is the dried fruit pulp of Aegle marmelos (bael), a tree of the citrus family (Rutaceae) native to the Indian subcontinent. It is an official drug in the Ayurvedic Pharmacopoeia of India (Part I, Volume I).

Does bael help diarrhea-predominant IBS?

Two trials suggest it might. A 1989 double-blind trial (n=169) of an Ayurvedic compound containing bael reported benefit for diarrhea-predominant IBS over placebo, though bael was not tested alone, so its individual contribution is unknown. Separately, a 226-patient randomized, double-blind crossover trial found 300 mg/day of dried bael fruit-powder extract significantly reduced stool frequency and loose stools in IBS-D (UEG Week e-poster). The latter was presented as a conference poster, not a peer-reviewed paper, and neither result has been replicated.

Does bilva help ulcerative colitis?

No human evidence was identified in the reviewed sources. Bael fruit extracts improved colitis in rat and mouse models, but animal results do not establish human efficacy (PMC3480795; Phytomedicine 2025).

What is the difference between unripe and ripe bael fruit?

Traditionally, the unripe or half-ripe fruit is the form used for diarrhea and dysentery; the ripe fruit is eaten as food (Pharmacognosy Magazine article). The clinical trial used a dried powdered extract of the fruit.

Is bilva safe?

Short-term trial use (two weeks) reported no significant side effects, but longer-term human safety data were not identified in the reviewed sources. Do not use it as a substitute for prescribed bowel-disease treatment.

Voices

The classical texts

Charaka Samhita: bilva for vataja atisara. In Chikitsa Sthana 19, the chapter on managing atisara (diarrhea and associated disorders), verses 26–29 name bilva among the drugs "useful for the cure of vataja atisara (diarrhea)"; verse 29 closes the group with grahi balyo rochanascha: constipating, strength-promoting, appetizing, "therefore beneficial for those with diarrhea." The same chapter carries a caution that modern summaries tend to skip: sangrahi (astringent, bowel-binding) therapy is not advised in the initial ama stage of diarrhea; the motions should not be stopped by constipating drugs while ama is still present. The grahi drugs are for what comes after. (Atisara Chikitsa, Charak Samhita online edition; chapter DOI: 10.47468/CSNE.2020.e01.s06.020)

Sushruta Samhita: dried green fruit for atisara. In the Uttara-Tantra's chapter on the treatment of atisara, the text prescribes "Yashti-madhu, (dried) green Vilva-fruit mixed with honey and sugar" as curative in atisara. That is the classical root of the unripe-fruit-for-diarrhea rule, stated long before anyone ran a trial. (Bhishagratna translation, proofread on Wikisource: Sushruta Samhita Vol 3, p. 223)

The unripe/ripe distinction, from the Nighantus. A 2020 review tabulating Bhavaprakasha, Shaligram, Kaiyadeva and Dhanwantari Nighantus puts it plainly: the unripe fruit is katu–tikta–kashaya (pungent, bitter, astringent) in rasa, ushna, deepana and grahi ("protect to intestine"); the ripe fruit is madhura, guru (heavy), vidahi, vishtambhi, hard to digest. That is the textual basis for the rule in the FAQ above: unripe for diarrhea, ripe as food. (Review of Bilva: A Marvelous Medicine, GJRA, March 2020)

Bilva root in Dashamoola. A 2022 drug review in the World Journal of Pharmaceutical Research catalogs bilva's classical groupings: Charaka's Shothahara, Arsoghna, Asthapanopaga and Anuvasanopaga vargas; Sushruta's Varunadi and Ambasthadi ganas, plus the Brihatpanchamoola: the five "great roots" that form the core of Dashamoola. The root belongs to Ayurveda's most-used compound group; the fruit pulp is the digestive drug. (Drug review of Bilva, WJPR 11(7), 2022, via WisdomLib)

Modern voices

BHU, 1989: a real randomized trial. Yadav SK, Jain AK, Tripathi SN and Gupta JP (Departments of Medicine and Kayachikitsa, Institute of Medical Sciences, Banaras Hindu University, Varanasi) ran a double-blind randomized trial in 169 IBS patients: an Ayurvedic compound of Aegle marmelos plus Bacopa monnieri against standard therapy and placebo, over six weeks. The Ayurvedic arm was effective in 64.9% of patients, behind standard therapy at 78.3% but well ahead of placebo at 32.7%, and was "particularly beneficial in diarrhoea predominant form as compared to placebo." The same abstract carries the two limits honestly: bael was not tested alone, so its share of the effect is unknown; and at follow-up beyond six months, neither active arm beat placebo at preventing relapse. (Full text via the POPLINE archive)

The Pune gastroenterologists, in their own words. Thorat et al.'s UEG Week e-poster concludes: "Treatment with dried powdered extract of Aegle Marmelos fruit is effective and safe in treatment of diarrhea in irritable bowel syndrome with diarrhea predominance (IBS-D). Further studies are necessary to isolate the active ingredient and subject it to clinical scrutiny." Note what they ask for: isolation of the active ingredient, and clinical scrutiny. One poster, no peer review, no replication yet. (e-poster PDF)

What I could not verify. No published interview with a named vaidya on bilva turned up in searchable sources, and no AYU or J-AIM human trial of bael for diarrhea or IBS surfaced. The verifiable human record is the 1989 BHU trial and the Pune poster above. No invented quotes, no anecdotes.

Sources

Disclaimer

This article is for educational purposes only and is not medical advice. Herbal products can interact with medications and are not suitable for everyone. Talk to a qualified healthcare practitioner before use — especially if you are pregnant, breastfeeding, managing a medical condition, or taking prescription medicines.