The purpose of this study was to compare the efficacy and tolerance of a single dose of the acetaminophen 400 mg-codeine 25 mg combination (ACC) aspirin 1000 mg (A) and a placebo (P) for the treatment of acute migraine attack. The study design was randomized, multicentre, double-blind and double dummy with cross-over on three periods. Of the 198 patients who had three attacks 29.8%, 52.3% and 49.7% had recorded the complete or almost complete disappearance of the pain at 2 h after P, A and ACC respectively. When compared with the placebo, the difference was significant for the A and ACC. When complete disappearance of pain at 2 h was used as a criterion, no significant difference was observed. These results enabled the sensitivity of the evaluation criteria suggested for clinical trials of migraine attack to be discussed.