Traditional Chinese medicine

AtractylodesAtractylodes macrocephala (bai zhu); A. lancea (cang zhu)

Bai zhu leads the classic Chinese spleen formulas; a 96-person IBS-D trial of Tong Xie Yao Fang found 79.2% vs 70.8% response, not significant.

Botanical name

Atractylodes macrocephala (bai zhu); A. lancea (cang zhu)

Part used

rhizome, usually stir-fried with bran before use

Also called

pinyin Bai zhu (A. macrocephala), Cang zhu (A. lancea) (白术 / 苍术); White atractylodes, Atractylodis macrocephalae rhizoma, Baekchul (Korean)

Used in

Traditional Chinese medicine

Taken for

Loose stools and diarrhea, Bloating, Appetite, Indigestion

Sold as

decoction, granules, pills, capsules, powder, dried slices

The plant

Atractylodes is the dried rhizome of two related daisy-family plants that Chinese medicine keeps apart. Bai zhu, from Atractylodes macrocephala, is the one sold as “white atractylodes”. Cang zhu, from Atractylodes lancea or A. chinensis, is a separate drug that appears in Ping Wei San. A label that says only atractylodes can mean either.

Bai zhu is cut into slices and, in most prescriptions, fried with wheat bran (chao bai zhu) or with earth before use, as the tradition prescribes. It then goes into a water decoction with other herbs, or into granules, pills and capsules. It is the “zhu” in Si Jun Zi Tang, Liu Jun Zi Tang, Shen Ling Bai Zhu San, Xiao Yao San, Tong Xie Yao Fang and Huo Xiang Zheng Qi San, which puts it in several of the tradition’s best-known digestive prescriptions.

How the traditions use it

Traditional Chinese medicine (about TCM)

Bai zhu is listed in the standard English materia medica as bitter, sweet and warm, entering the spleen and stomach channels, with the actions of strengthening the spleen, tonifying qi, drying dampness, stopping sweating and calming the fetus. Cang zhu is classed as acrid, bitter and warm, with a stronger drying action and less tonifying one, and is the lead herb of Ping Wei San for what the texts call dampness encumbering the spleen, which includes a heavy abdomen, nausea and loose stools. In the tradition’s vocabulary the spleen is the organ of transformation, and bai zhu is the herb for a spleen that has gone weak with dampness, a picture that includes poor appetite, fullness after eating and loose stools. All of this is the tradition’s classification and not physiology.

What is in it

A Journal of Ethnopharmacology review lists more than 79 compounds in A. macrocephala, including sesquiterpenoids, triterpenoids, polyacetylenes, coumarins and polysaccharides, and ties much of the reported activity to the sesquiterpenoids, polysaccharides and polyacetylenes. In animals and cell studies the extract and individual compounds were reported to improve gastrointestinal function and to have anti-inflammatory activity. These are laboratory and animal findings, and the review itself says the mechanisms and long-term toxicity are not yet well understood.

What the human trials show

We could not find a placebo-controlled trial of atractylodes on its own for a gut outcome. The human data are trials of formulas, and they are uneven.

Tong Xie Yao Fang is the formula built on bai zhu: white atractylodes, white peony, tangerine peel and saposhnikovia. A meta-analysis of 11 trials with 985 adults who had diarrhea-predominant IBS found it better than placebo and than Western drugs for global symptom improvement, with moderate certainty by the GRADE system, but the authors called for more trials. A pooled analysis of the modified version across 23 trials and 1,972 patients gave an odds ratio of 4.04 (95% CI 3.09 to 5.27) against routine drugs. The most rigorous test came later: a double-blind, placebo-controlled phase II trial in 96 adults with IBS-D gave 3.7 g twice a day for 8 weeks. Symptom response was 79.2 percent (38 of 48) on the formula and 70.8 percent (34 of 48) on placebo, and the difference was not significant. Both groups improved a lot, which fits a review of IBS trials that put the herbal placebo response at 37 percent.

Other formulas that contain bai zhu: a meta-analysis of 14 trials with 1,158 adults who had chronic diarrhea found that Shen Ling Bai Zhu San gave greater patient-reported satisfaction than conventional medicine alone, with no increase in adverse events. A 52-trial analysis of Liu Jun Zi Tang for functional dyspepsia is on the ginseng page.

Not tested: bai zhu alone in a controlled trial for any digestive symptom, and cang zhu in Ping Wei San in a randomized trial we could find.

How much the studies and the texts used

In the 96-person placebo-controlled IBS-D trial, Tong Xie Yao Fang was given as 3.7 g of granules twice a day before meals for 8 weeks. The traditional preparation is a water decoction of the stir-fried slices with the other herbs of the formula, taken warm in divided doses; the formula versions in the meta-analyses were decoctions that differed in gram weights between trials, so no single herb dose can be read off them. Pills, granules and capsules of the formulas are sold ready-made, and bai zhu on its own may also be sold as a powder or extract, without a trial-based dose.

Side effects and cautions

The Tong Xie Yao Fang placebo trial recorded one adverse event on the formula (sinus arrhythmia) and two on placebo (raised liver enzymes and a weakly positive fecal blood test), none serious, and the Shen Ling Bai Zhu San review found no increase in adverse events. A review of A. macrocephala notes that long-term toxicity has not been well studied. The texts use bai zhu to “calm the fetus”, which is the tradition’s claim and not safety data. On product quality, a New York laboratory screen of 90 Chinese herbal and patent medicine samples found Western pharmaceuticals in 5 of them, nine different drugs in all, and two of the five held undeclared or mislabeled substances; the screen did not single out atractylodes products.

Interactions

No interaction study of atractylodes with a medicine turned up in our reading, and none of the reviews we read flags one. The trial data are on formulas, and the formulas it appears in also hold ginseng, licorice, ginger and tangerine peel, so the interaction notes for those herbs apply to a finished formula and cannot be separated out for bai zhu.

Atractylodes on the shelf: the products that contain it

The products here name atractylodes among their actives. How much of it a serving holds, and whether that matches any trial, is on each page.

Often paired or compared

The questions that come up

Sources

• Liang SB et al., "Chinese herbal formula Tongxie Yaofang granules for diarrhoea-predominant irritable bowel syndrome: a randomised, double-blind, placebo-controlled, phase II trial", BMJ Open 2025;15:e088410 pubmed.ncbi.nlm.nih.gov/39870499
• Liang SB et al., "Systematic review and meta-analysis of Chinese herbal formula Tongxie Yaofang for diarrhea-predominant irritable bowel syndrome", Front Pharmacol 2022;13:904657 pubmed.ncbi.nlm.nih.gov/36091782
• Dai YK et al., "Efficacy and safety of Modified Tongxie Yaofang in diarrhea-predominant irritable bowel syndrome management: A meta-analysis of randomized, positive medicine-controlled trials", PLoS One 2018;13:e0192319 pubmed.ncbi.nlm.nih.gov/29408906
• Wang H et al., "Herbal Formula Shenling Baizhu San for Chronic Diarrhea in Adults: A Systematic Review and Meta-analysis", Integr Cancer Ther 2022;21:15347354221081214 pubmed.ncbi.nlm.nih.gov/35635135
• Huang X, Shao S, "Meta-analysis of modified Sijunzi decoction for the treatment of chronic atrophic gastritis", Medicine (Baltimore) 2024;103:e37648 pubmed.ncbi.nlm.nih.gov/38669406
• Huang K et al., "Herbal placebo response in clinical trials on irritable bowel syndrome: a systematic review and meta-analysis", Front Pharmacol 2024;15:1475366 pubmed.ncbi.nlm.nih.gov/39669195
• Zhu B et al., "The traditional uses, phytochemistry, and pharmacology of Atractylodes macrocephala Koidz.: A review", J Ethnopharmacol 2018;226:143-67 pubmed.ncbi.nlm.nih.gov/30130541
• Miller GM, Stripp R, "A study of western pharmaceuticals contained within samples of Chinese herbal/patent medicines collected from New York City’s Chinatown", Leg Med 2007;9:258-64 pubmed.ncbi.nlm.nih.gov/17652006
• Bensky D, Clavey S, Stoger E, Chinese Herbal Medicine: Materia Medica, 3rd ed., Eastland Press, 2004 (nature, flavor, channels and actions as the tradition gives them) www.eastlandpress.com/products/chinese-herbal-medicine-materia-medica-portable-3rd-ed
• Bensky D, Barolet R, Ellis A, Scheid V, Chinese Herbal Medicine: Formulas and Strategies, 2nd ed., Eastland Press, 2009 (formula compositions) www.eastlandpress.com/products/chinese-herbal-medicine-formulas-strategies-portable-2nd-edition