Ginger (Zingiber officinale): An alternative for the prevention of postoperative nausea and vomiting. A meta-analysis.

BACKGROUND: Postoperative nausea and vomiting (PONV) is a distressing outcome related to surgeries. Traditionally, ginger has been used in the treatment of nausea and vomiting for thousands of years. Recently, several randomized, placebo-controlled clinical trials (RCTs) have been conducted to evaluate the efficacy of ginger in PONV. PURPOSE: To systematically evaluate the efficacy of ginger on postoperative nausea and vomiting (PONV) compared to placebo, based on RCTs. STUDY DESIGN: The meta-analysis was reported following the PRISMA guidelines using the PICO format, and it was registered with the PROSPERO register. METHODS: PubMed, Embase, the Cochrane Central Register of Controlled Trials and Web of Science were searched for relevant studies. Human, placebo-controlled clinical studies of patients undergoing any types of surgery, receiving pharmacological doses of ginger per os were included. Only clinical trials with explicit description of the ginger preparation used were analysed. No language or publication year restrictions was applied. RESULTS: Ten randomized trials including a total of 918 patients were pooled for the statistical analysis. The present meta-analysis supports that ginger has a significant effect on the severity of PONV based on visual analogue scale (VAS) results: in a fixed effects model the pooled standardized mean difference (SMD) was -0.247 (favouring ginger; [LL]: -0.455, [UL]: -0.040, p-value: 0.019). Moreover, our results suggest that ginger reduces the incidence of postoperative nausea and vomiting, as well antiemetic drug demand; however, these effects are not statistically significant compared to placebo, which may be explained by underdosing. CONCLUSIONS: According to our thorough meta-analysis ginger is safe and well tolerated, and decreases the severity of PONV, and may lower the incidence of postoperative nausea and vomiting, which in turn may reduce antiemetic drug demand, suggesting that ginger may be a useful alternative to antiemetic medications to alleviate PONV.