Effect of herbal medicine on postoperative nausea and vomiting after laparoscopic surgery: A systematic review and meta-analysis

Background: Traditionally, herbal medicines have been used to alleviate nausea and vomiting; however, a comprehensive clinical evaluation for postoperative nausea and vomiting (PONV), especially after laparoscopic surgery, remains limited. This review aimed to evaluate the efficacy and safety of herbal medicine as an alternative therapy to prevent and manage nausea and vomiting after laparoscopic surgery compared with untreated, placebo, and Western medicine groups. Methods: We searched 11 databases, including EMBASE, PubMed, and the Cochrane Library, to collect randomized controlled trials (RCTs) of herbal medicines on PONV after laparoscopic surgery on July 7, 2022. Two independent reviewers screened and selected eligible studies, extracted clinical data, and evaluated the quality of evidence using the Cochrane risk-of-bias tool. The primary outcome was the incidence of PONV, whereas the secondary outcomes included the frequency and intensity of PONV, symptom improvement time, antiemetic requirement frequency, and incidence of adverse events. Review Manager Version 5.3. was used for the meta-analysis. Results: We identified 19 RCTs with 2726 participants comparing herbal medicine with no treatment, placebo, and Western medicine. The findings showed that compared with no treatment, herbal medicine demonstrated significant effects on vomiting incidence (risk ratio [RR] = 0.43, 95% confidence interval [CI] 0.32-0.57, P < .00001). Compared with placebo, herbal medicine revealed a significant effect on the severity of nausea 12 hours after laparoscopic surgery (standardized mean difference = -2.04, 95% CI -3.67 to -0.41, P = .01). Herbal medicines showed similar effects with Western medicine on the incidence of postoperative nausea (RR = 0.94, 95% CI 0.63-1.42, P = .77) and vomiting (RR = 0.68, 95% CI 0.25-1.84, P = .45). Furthermore, comparing the experimental group containing herbal medicine and control group excluding herbal medicine, adverse events were considerably lower in the group with herbal medicine (RR = 0.45, 95% CI 0.27-0.72, P = .001). Conclusion: Herbal medicine is an effective and safe treatment for nausea and vomiting secondary to laparoscopic surgery. However, the number of studies was small and their quality was not high; thus, more well-designed RCTs are warranted in the future.