A Combination of Peppermint Oil and Caraway Oil for the Treatment of Functional Dyspepsia: A Systematic Review and Meta-Analysis

A combination of peppermint oil and caraway oil (POCO) with its unique properties has been shown clinical benefits for FD. However, the potent statistical data to confirm its effects are lacking. This meta-analysis thus aimed at evaluating the efficacy and safety of POCO compared with placebo in treating patients with FD. We searched CENTRAL, PubMed, EMBASE (Ovid), Web of Science, Google Scholar, China National Knowledge Infrastructure database, Wanfang, and VIP databases for randomized clinical trials (RCTs) up to June 2019. Dichotomous data were shown as a risk ratio (RR) with 95% confidence intervals (CIs). All data were analyzed by Review Manager 5.2 software. The search identified 382 citations, and 5 RCTs (578 participants) were included. POCO showed a statistically significant effect in global improvement of FD symptoms (RR for not much or very much improvement 0.59, 95% CI: 0.49 to 0.71, P < 0.00001, I(2) 36%, NNT 3) and improvement in epigastric pain (RR 1.61, 95% CI: 1.28 to 2.03, P < 0.0001, I(2) 0%, NNT 3). There were no significant differences in the total number of adverse events between POCO and placebo (NNH 40). In conclusion, this is the first meta-analysis to assess the effects of POCO in FD. POCO is an effective and safe short-term treatment for FD. However, current findings are based on smaller sample sizes and low/very low quality of the evidence. More well-designed RCTs with large sample sizes of FD patients are required.