Systematic Review on the Efficacy of Topical Arnica montana for the Treatment of Pain, Swelling and Bruises

Abstract Background: Arnica montana has been used as a remedy for centuries, and is common today for the treatment of pain, swelling and bruises. However its efficacy remains controversial. The authors systematically review the literature on the efficacy of A. montana applied topically. Literature searches of the main electronic databases on topical Arnica were performed. Also relevant experts and the herbal industry were consulted. Data was analyzed and the methodological quality assessed. Findings: Eleven controlled trials were found, five in volunteers and six in patients. Heterogeneity in the health conditions, Arnica dosage, co-interventions, and effects measurements was high, and many studies had important methodological flaws. Often, the number of participants was small and there were potential risks for bias. We identified a trend to better quality as the studies were more recent. Even the better studies showed at most a modest effect. Conclusion: The efficacy of Arnica in doses of 10% and below is not supported by the available evidence. More research is needed to determine if higher doses would be effective and remain safe.