Chinese herbal medicine versus probiotics for irritable bowel syndrome: a systematic review and meta-analysis of randomized controlled trials

Abstract Introduction Chinese herbal medicine (CHM) and probiotics are two complementary and alternative therapies often used for irritable bowel syndrome (IBS). This study evaluates the efficacy and safety of CHM compared with probiotics for IBS. Methods 11 databases were searched (up until March, 2020) for randomized controlled trials of IBS. Risk of bias was evaluated. RevMan 5.3 was used for data synthesis. Trial sequential analysis (TSA) was used to control for risk of random errors. Results 47 trials were included. Unclear risk of bias was in almost domains of included trials. CHM had advantages over probiotics for improving overall symptoms of IBS-Diarrhea (IBS-D) (RR 1.24, 95% CI 1.18-1.30, 3207 patients, I2 = 55%, very low certainty). The heterogeneity might be associated with different diagnostic criteria, duration of treatment, probiotic compositions, and types of CHM. CHM might be better than probiotics when the duration of treatment more than 4 weeks (RR 1.26, 95% CI 1.20-1.33, 2669 patients, very low), and the formulae represented by Tongxie Yaofang appeared to be better than triple Bifidobacterium preparations for improving overall symptoms of IBS-D (RR 1.33, 95% CI 1.20-1.47, 476 patients). CHM might reduce relapse rate compared with probiotics (RR 0.27, 95% CI 0.18-0.40, 382 patients, very low). Adverse events were mainly gastrointestinal symptoms. Conclusions Very low quality evidence suggests that CHM may be better than probiotics when the duration of treatment lasted more than 4 weeks for improving overall symptoms of IBS-D; and CHM may be better than probiotics for reducing relapse rates of IBS-D.