The preventive and relieving effects of ginger on postoperative nausea and vomiting: A systematic review and meta-analysis of randomized controlled trials

Background: Postoperative nausea and vomiting are common uncomfortable symptoms experienced by patients. Besides drugs, non-pharmaceutical therapies such as herbal medicine therapy are available. Ginger has played a therapeutic role in patients undergoing chemotherapy and pregnant women, but results from postoperative patients are inconsistent. Objectives: The aim of this study was to examine and evaluate the preventive effect of ginger on postoperative nausea and vomiting. Design: A systematic review and meta-analysis of randomized controlled trials Methods: Two independent researchers searched Chinese and English databases from their inception dates to November 2020. The Chinese databases used were CNKI and SinoMed, and the English databases used were PubMed, Embase, and the Cochrane Library. We only included randomized controlled trials. The primary outcomes were nausea score, presented as standard mean difference, and the number of vomiting episodes, presented as risk ratio. The secondary outcomes were side effects and antiemetic drug use, presented as risk ratios. We used the random-effects model. Results: Fourteen randomized trials with a total of 1,506 patients were pooled. At the different time points, the control group had higher postoperative nausea scores than the experimental group, and the differences were significant between the ginger and placebo groups at 2, 6, and 12 h after operation, with standard mean differences and 95% confidence intervals of -1.10 and -1.95 to -0.25, -1.54 and -3.05 to -0.03, and -2.04 and -3.67 to -0.41, respectively. Except in the recovery room, no statistically significant correlation was found between ginger intake and postoperative vomiting, postoperative nausea and vomiting, or antiemetic drug use. Conclusion: The results of this meta-analysis demonstrate that ginger can reduce postoperative nausea but showed no significant difference in the incidence rates of postoperative vomiting, postoperative nausea and vomiting, and antiemetic drug use. More high-quality and rigorous trials are needed to elucidate the relationship between ginger intake and the reduction in the incidence of postoperative nausea and vomiting. (C) 2021 Elsevier Ltd. All rights reserved.