BACKGROUND: To critically assess the evidence of modified xiaoyao san (MXS) for treating functional dyspepsia (FD). METHODS: Systematic literature searches were carried out on the Medline database, CNKI database, Wanfang Data, VIP Information and the Cochrane Library. All randomized clinical trials of MXS for treating FD were included. Weighted means and 95% confidence intervals were calculated and sensitivity analyses were carried out. RESULTS: Thirty-three potentially relevant articles were retrieved for further evaluation. Fourteen were suitable for inclusion in the meta-analysis. There was evidence that MXS compared with prokinetic drugs reduced symptoms (odds ratio 3.26, 95% CI 2.24 to 4. 47). There was evidence that MXS + prokinetic drugs compared with prokinetic drugs reduced symptoms (odds ratio 4.32, 95% CI 2.64 to 7.08). CONCLUSION: MXS appears to be more effective compared to prokinetic drugs in the treatment of FD and no serious side-effects were identified. However, the evidence remains weak due to publication bias and methodological flaws, which may amplify the therapeutic benefit of MXS.

Qin F, et al.: J Gastroenterol Hepatol. 2009 Aug;24(8):1320-5 (


Xiao Yao San is a classical Chinese herbal formula published in 1087 in Imperial Grace Formulary of the Tai Ping Era (Tai Ping Hui Min He Ji Ju Fang). Traditionally, it is used for Liver Qi stagnation with Blood deficiency. Clinically, it is used mostly in depression-related diseases in Chinese medicine. A recent systematic review of 26 randomized clinical trials (involving 1837 patients) of Xiao Yao San revealed its effectiveness on depression (see below).

Jia Wei Xiao Yao San (JWXYS) is a modified version of Xiao Yao San recorded in 1602 in Rules of Conformation and Therapy (Zheng Zhi Zhun Sheng). Recently, it has been studied for its usage in functional dyspepsia (FD), a gastrointestinal disorder that affects an estimated 20% of Americans. One of the conventional treatments of FD is low dose anti-depressant drugs. A randomized clinical trial funded by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) is currently underway to examine the effectiveness and mechanisms of the tricyclic antidepressant amitriptyline and the selective serotonin-reuptake inhibitor (SSRI) escitalopram in functional dyspepsia. Interestingly, many studies already conducted in the Chinese medicine field have shown that JWXYS, a commonly used herbal formula for depression-related disorders, may have beneficial roles in FD. A meta-analysis of multiple clinical trials showed that JWXYS is more effective compared to prokinetic drugs in the treatment of FD. A clinical study of 20 patients with FD indicated that the formula improved the symptoms as well as electrogastrography (EGG). Please read on below for details of the studies.