Introduction and Aim: Ginger capsules are an effective non-pharmacological treatment for improving postop-erative nausea and vomiting (PONV), but the results of previous reviews have been inconclusive. We synthe-sized the available evidence to evaluate the effectiveness of ginger capsules on PONV. 
Method: Using relevant keywords, data resources including PubMed/MEDLINE, SCOPUS, WoS, Embase, CENTRAL, CINAHL, and RCT registration systems were searched from January 1990 to June 2022. RCTs evaluating the antiemetic effect of ginger capsules on the incidence and severity of nausea and vomiting in adults aged 18 years and older. ProQuest and oatd.org were searched for thesis/dissertation. The Verhagen checklist for RCTs was used for the quality assessment. Mean and standard deviations of the severity of nausea and the number of incidences of nausea and vomiting were combined using the random effect model. We conducted the meta-analysis using Stata 14.1. 
Finding: In the primary search, 5584 studies were identified, and ultimately 20 studies were included in the systematic review. The subgroup analysis showed that ginger capsules reduced nausea severity and incidence of vomiting two hours after the operation (WMD: 0.97, 95% CI: -1.55 to -0.39, P = 0.001; RR:0.66, CI:0.50020-0.87). No statistically significant reduction in the nausea severity and incidence of nausea/vomiting immediately and after six and twenty-four hours postoperatively was observed (p>0.05). 
Conclusion: This review provides evidence regarding the potential benefits of ginger capsules for PONV. Fur-ther rigorous RCTs are needed to solidify the conclusion regarding the effectiveness of ginger capsules.