Is ginger a clinically relevant antiemetic? A systematic review of randomized controlled trials

Background and Objective: The aim of this systematic review was to evaluate the clinical impact of ginger ( Zingiber officinale) as an antiemetic. Methods: A systematic search of the literature was performed using the databases of MEDLINE, EMBASE, and the Cochrane- Library. Results: Of 100 published reports discerned as potentially relevant, 24 randomized controlled trials were evaluated, covering 1073 patients which had received ginger. Of these reports, 16 contained information regarding the antiemetic activity of the phytotherapeutic agent against kinetosis, postoperative nausea and vomiting ( PONV), and morning sickness and hyperemesis gravidarum, respectively. Only a few studies were eligible for a quantitative analysis (meta-analysis). Thus, the majority of the reports were analyzed descriptively. To analyze the potential side effects of the drug, 15 reports with 777 patients were eligible. Of these, 3.3% suffered from slight side effects, mainly mild gastrointestinal symptoms and sleepiness, both not requiring specific treatments. One severe adverse event was reported in a study: an abortion occurred in the 12th week of gestation. However, a total of 136 patients were treated with ginger within the first trimenon of pregnancy without complications. Conclusion: There is no clear evidence for the efficacy of ginger in the treatment of PONV and of kinetosis. The results for the treatment of nausea and vomiting in pregnancy are encouraging, however, ginger should be applied for the time being only in controlled clinical studies. Applied in daily doses up to 6 g ginger seems to be a drug with few side effects.