We performed a prospective, randomized, double-blind, placebo-controlled trial of intravenous lidocaine (1 mg/kg) in the treatment of acute migraine. Thirteen subjects were randomly allocated to receive intravenous lidocaine and 12 received intravenous normal saline. Subjects scored the intensity of headache and nausea on separate visual analogue scales before the injection and at 10 and 20 min after injection. At 20 min, the mean pain intensity score was 80% of initial intensity in the lidocaine group and 82% in the placebo group. The difference was not statistically significant; at 20 min, the 95% confidence interval for the difference between the two groups in mean percentage of initial pain score was 2 +/- 29%. At the dose studied, intravenous lidocaine has, at best, only a modest effect in acute migraine.