Homeopathic arnica: just a placebo.
Four placebo-controlled trials of homeopathic dilutions of arnica in treating trauma have been sufficiently robust to give interpretable results. In all of them homeopathic arnica was no more effective than the placebo.
D018650:Arnica; D002986:Clinical Trials as Topic; D006705:Homeopathy; D006801:Humans; D015201:Meta-Analysis as Topic; D015990:Placebo Effect