A systematic review of the evidence for topical use of ginger.

Background: The use of ginger as a topical intervention is widely advocated in the popular media. However, there has been no attempt to date to synthesize the evidence for topically administered ginger.

Objective: To systematically review and synthesize the best available evidence of effectiveness for topical ginger in any condition.

Data Sources: CAM on PubMed, CINAHL, Google Scholar, MEDLINE, National Library of Australia, The Cochrane Library, TRIP, pertinent texts, and bibliographies of relevant papers.

Study Selection: Data sources were systematically searched for studies investigating the clinical effectiveness of topical ginger, in any form and for any condition, regardless of study design. Studies were limited to those published between 1980 and 2010, and published in English, Mandarin, Cantonese, or Taiwanese.

Data Extraction: Data were extracted by two authors, independently, using standardized templates.

Data Synthesis: Four studies met the inclusion criteria, including three randomized controlled trials and one non-randomized controlled trial. All studies differed in terms of study population, outcome measures, comparative interventions, and dose and form of ginger used, and thus, were not amenable to meta-analysis. Findings from all trials favored usage of ginger for most outcomes. However, the small sample sizes and inadequate methodological reporting indicate a high risk of bias and the need for caution when interpreting these results.

Conclusions: Few studies have investigated the effectiveness of topically administered ginger for any condition. Until the findings of these studies are corroborated by more robust research, and the safety of ginger is adequately established, clinicians should remain cautious about using topical ginger in clinical practice.