Efficacy of homeopathic arnica: a systematic review of placebo-controlled clinical trials.

BACKGROUND: The efficacy of homeopathic remedies has remained controversial. The homeopathic remedy most frequently studied in placebo-controlled clinical trials is Arnica montana. OBJECTIVE: To systematically review the clinical efficacy of homeopathic arnica. MATERIALS AND METHODS: Computerized literature searches were performed to retrieve all placebo-controlled studies on the subject. The following databases were searched: MEDLINE, EMBASE, CISCOM, and the Cochrane Library. Data were extracted in a predefined, standardized fashion independently by both authors. There were no restrictions on the language of publications. RESULTS: Eight trials fulfilled all inclusion criteria. Most related to conditions associated with tissue trauma. Most of these studies were burdened with severe methodological flaws. On balance, they do not suggest that homeopathic arnica is more efficacious than placebo. CONCLUSION: The claim that homeopathic arnica is efficacious beyond a placebo effect is not supported by rigorous clinical trials.