Is ginger a relevant antiemetic for postoperative nausea and vomiting?

Objective: Ginger (Zingiber officinale) has traditionally been used in China for gastrointestinal symptoms, including nausea and vomiting. A recent systematic review on the possible antiemetic effect of ginger for various indications, including PONV, morning sickness, and motion sickness, concluded that ginger was a promising antiemetic herbal remedy, but the clinical data were insufficient to draw firm conclusions. Since that publication, additional data has accumulated and thus an updated meta-analysis was performed. Methods: A systematic search of the literature was performed using different search strategies in MEDLINE, EMBASE, and the Cochrane Library. Six randomized controlled trials including 538 patients were identified investigating ginger to prevent postoperative nausea and vomiting (PONV). Data on the incidences of PONV, nausea, vomiting, and the need for rescue antiemetics within the first 24 postoperative hours were extracted and the pooled relative risk and the numbers needed to treat (NNT) were calculated using a random effects model. Results: The pooled relative risk to suffer from PONV after pre-treatment with ginger was 0.84 (95%-confidence interval 0.69 - 1.03). About 11 patients must be treated with ginger for one additional patient remaining free from PONV (NNT: 11; 95%-Cl: 6 - 250). Results for nausea, vomiting, and need for antiemetic rescue treatment are similar. Conclusion: Ginger is not a clinically relevant antiemetic in the PONV setting.