Randomised Clinical Trial

Tong-Xie-Yao-Fang Granules Versus Placebo for Patients With Diarrhoea-Predominant Irritable Bowel Syndrome

M. Chen; T.-C. Tang; Y. Wang; J. Shui; X.-H. Xiao; X. Lan; P. Yu; C. Zhang; S.-H. Wang; J. Yao; H. Zheng; D.-Q. Huang


Aliment Pharmacol Ther. 2018;48(2):160-168. 

In This Article

Abstract and Introduction


Background: Tong–Xie–Yao–Fang (TXYF) is a Chinese herbal formula for treating chronic diarrhoea accompanied by abdominal pain. The results were inconsistent in previous trials examining its effect.

Aim: To study the efficacy of TXYF granules for treating diarrhoea–predominant irritable bowel syndrome (IBS–D).

Methods: We performed a double–blind, placebo–controlled randomised trial and enrolled 160 participants with IBS–D. The participants had VAS scores ≥3 cm in IBS–D global symptoms and ≥2 days in a week with abdominal pain and loose stools (Bristol score 5, 6 or 7). They were randomly assigned to received TXYF or placebo during a treatment period of 4 weeks, and they were followed up for 8 weeks after treatment. The primary outcome was adequate relief of IBS–D global symptoms for at least 2 of 4 weeks during weeks 1–4. Secondary outcomes included mean weekly VAS scores of IBS–D major symptoms, mean weekly stool frequency, mean weekly Bristol score, and adverse events.

Results: 155 of 160 patients completed the trial. We found a significantly higher rate of adequate relief of global symptoms in TXFY group during weeks 1 to 4 (57.5% vs 37.5%, χ 2 = 5.6391, P = 0.017); logistic regression analysis showed a similar result (OR 2.2, 95% CI 1.2–4.4, P = 0.016). Most of the secondary outcomes showed superiority of TXYF over placebo in weekly assessment from week 3 to week 7. The adverse event rate was low in both groups (3.8% vs 3.8%, P = 1.000).

Conclusion: During a 4 week trial, TXFY granules were superior to placebo in controlling symptoms of IBS–D.


Irritable bowel syndrome (IBS) is a chronic functional bowel disorder characterised by abdominal pain and altered bowel function. The altered bowel function defines the IBS subtypes, of which principally manifesting with diarrhoea is classified as diarrhoea–predominant IBS (IBS–D).[1] IBS–D is highly prevalent,[2,3] and it causes low work productivity[4,5] and low quality of life.[6]

Current options are limited for the treatment of IBS–D.[1] Several treatments are proposed, but they all have some disadvantages that limit their use in clinical practice. As initial treatment, dietary and lifestyle modification have variable effects on IBS–D, and their effects are often less than optimal.[7] Alosetron, one of the 5–HT3 antagonists, is effective for abdominal pain and discomfort, but it causes a dose–dependent increase in adverse events (constipation and ischaemic colitis).[8,9] Rifaximin, an antibiotic treatment, shows promising effect on relieving IBS–D global symptoms.[10–12] However, questions are raised about potential development of antibiotic resistance in repeated and long–term use of rifaximin.[9,13] Opioid agonists are reported to be possibly effective for IBS–D, but adverse events related to their use are still a major concern and therefore they are still under investigation.[9,14]

Tong–Xie–Yao–Fang (TXYF) is a Chinese herbal formula for the management of chronic diarrhoea accompanied by abdominal pain; it has been used in China for nearly 600 years. Animal studies showed its efficacy in relieving smooth muscle contraction and decreasing visceral hypersensitivity,[15–17] and the efficacy may be related to the regulation of 5–hydroxytryptamine and substance P in colonic tissues.[15] Clinical trials showed inconsistent results. A study from Hong Kong found TXYF with little effect on the improvement of IBS–D global symptoms,[18] but a trial from mainland China found it with positive effect.[19] Systematic reviews confirmed the effectiveness of TXYF,[20,21] but they also concluded the warranty of new trials in this field because of the quality of included trials, the heterogeneity in constituents of TXYF formula, and variety in its clinical effect across the trials.

The objective of our trial is to examine the efficacy of oral administration of TXYF granules (aqueous extract of the TXYF formula that is officially recorded in the Chinese textbook) in the treatment of IBS–D through a placebo–controlled randomised trial.