Efficacy of Chinese Herbal Medicine for Diarrhea-Predominant Irritable Bowel Syndrome: A Meta-Analysis of Randomized, Double-Blind, Placebo-Controlled Trials

Objective. To explore the efficacy of Chinese herbal medicine in treating diarrhea-predominant irritable bowel syndrome (D-IBS). Methods. Four English and four Chinese databases were searched through November, 2015. Randomized, double-blind and placebo-controlled trials were selected. Data extraction and quality evaluation were performed by two authors independently. RevMan 5.2.0 software was applied to analyze the data of included trials. Results. A total of 14 trials involving 1551 patients were included. Meta-analysis demonstrated superior global symptom improvement (RR = 1.62; 95% CI 1.31, 2.00; P < 0.00001; number needed to treat = 3.6), abdominal pain improvement (RR = 1.95; 95% CI 1.61, 2.35; P < 0.00001), diarrhea improvement (RR = 1.87; 95% CI 1.60, 2.20; P < 0.00001), pain threshold assessment (MD = 54.53; 95% CI 38.76, 70.30; P < 0.00001), and lower IBS Symptom Severity Score (SMD = -1.01; 95% CI -1.72, -0.30; P = 0.005), when compared with placebo, while for defecation threshold assessment, quality of life, and adverse events, no differences were found between treatment groups and controlled groups. Conclusion. This meta-analysis shows that Chinese herbal medicine is an effective and safe treatment for D-IBS. However, due to the small sample size and high heterogeneity, further studies are required.