Zingiberis rhizoma: a comprehensive review on the ginger effect and efficacy profiles.

Zingiberis rhizoma is used as a broadspectrum antiemetic. We, therefore, conducted a comprehensive review of the literature to summarize the pharmacological and clinical effects of this popular plant material. Although clinical and experimental studies suggest that ginger has some antiemetic properties, clinical evidence beyond doubt is only available for pregnancy-related nausea and vomiting. Meta-analyses could not demonstrate the postoperative antiemetic effectiveness, and effect in motion sickness or nausea/vomiting of other ethiology. It also remains to be confirmed that proprietary ginger preparations are clinically useful to alleviate osteoarthritic or other pain, although there is no doubt that ginger constituents interfere with the inflammatory cascade and the vanilloid nociceptor. Ginger exerts in vitro antioxidative, antitumorigenic and immunomodulatory effects and is an effective antimicrobial and antiviral agent. Animal studies demonstrate effects on the gastrointestinal tract, the cardiovascular system, on experimental pain and fever, antioxidative, antilipidemic and antitumor effects, as well as central and other effects. The most relevant human pharmacological studies require a confirmatory study to exclude interaction of ginger preparations with platelet aggregation. Pharmacokinetic data are only available for [6]-gingerol and zingiberene. Preclinical safety data do not rule out potential toxicity, which should be monitored especially following ginger consumption over longer periods.