To evaluate the efficacy of homeopathy in preventing migraine attacks and accompanying symptoms, a randomised, double-blind, placebo-controlled clinical trial was conducted. There was a one-month registration period without treatment, followed by four months individualised homeopathic treatment or identical placebo. Patients were stratified for common or classical migraine. Seventy-three patients were randomised, 68 completed the trial. Baseline values were similar in the two groups. Both the homeopathy and placebo groups had reduction in attack frequency, pain intensity and drug consumption, with a statistically non-significant difference favouring homeopathy. Migraine diaries showed no difference between groups. The neurologists' trial evaluation showed a statistically significant reduction in attack frequency in the homeopathy group (P= 0.04) and non-statistically significant trends in favour of homeopathy for pain intensity and overall evaluation. Further research, with improved trial design, on the possible role of homeopathy in migraine prophylaxis is justified.