Herbal medicine in the treatment of functional gastrointestinal disorders: A systematic review with meta-analysis.

BACKGROUND AND AIMS: The efficacy of herbal medicines (HMs) for functional gastrointestinal disorders (FGIDs) including irritable bowel syndrome (IBS), functional dyspepsia (FD) and functional constipation (FC) is controversial. A systematic review with meta-analysis was conducted to determine their effectiveness for FGIDs. METHODS: We searched the following electronic databases till July 2019 with English language restriction: The Cochrane Library, EMBASE and PUBMED. Randomized double-blind controlled trials of HMs compared with placebo or conventional pharmacological drugs for adult FGIDs patients were included. RESULTS: In total, 49 trials involving 7396 participants with FGIDs were included. The risk of bias was low in 9, unclear in 36, and high in 4 trials. More than 33 different herbal formulae were tested. HMs demonstrated statistically significant benefits for symptom improvement compared with placebo in 46 trials (RR= 1.67, 95% CI 1.48-1.88). When compared with conventional pharmacological therapy in 5 trials, HMs were found to be non-inferior (RR= 1.10, 95% CI 1.03-1.18). The number of trials with regards to FD, IBS and FC were 19, 23 and 7 respectively. Subgroup analysis found that HMs were better than placebo in alleviating symptoms for FD (RR= 1.50, 95% CI 1.32-1.69), IBS (RR= 1.62, 95% CI 1.32-1.97) and FC (RR= 3.83, 95% CI 2.26-6.50). HMs tended to have more patients with adverse events than placebo, but similar to conventional pharmacological drugs. CONCLUSIONS: Our findings provide a positive signal for HMs as a potentially well-tolerated and effective treatment for FGIDs, deserving further examination in high-quality trials.