Efficacy of ginger for nausea and vomiting: a systematic review of randomized clinical trials

Ginger (Zingiber officinale) is often advocated as beneficial for nauseaand vomiting. Whether the herb is truly efficacious for this condition is,however, still a matter of debate. We have performed a systematic review ofthe evidence from randomized controlled trials for or against the efficacyof ginger for nausea and vomiting. Six studies met all inclusion criteriaand were reviewed. Three on postoperative nausea and vomiting wereidentified and two of these suggested that ginger was superior to placeboand equally effective as metoclopramide. The pooled absolute risk reductionfor the incidence of postoperative nausea, however, indicated anon-significant difference between the ginger and placebo groups for ginger1 g taken before operation (absolute risk reduction 0.052 (95% confidenceinterval -0.082 to 0.186)). One study was found for each of the followingconditions: seasickness, morning sickness and chemotherapy-induced nausea.These studies collectively favoured ginger over placebo.