A prospective, double-blind, crossover study was conducted of the effectiveness of dihydroergotamine (DHE) vs. placebo in the treatment of acute migraine in the emergency department. Thirty-seven patients were enrolled. By 60 minutes after treatment, those receiving DHE first had significantly better relief of pain than those receiving it later. Side effects were fairly common but were minor and did not necessitate terminating treatment. Eleven per cent of patients had significant relief of pain with prochlorperazine pre-treatment alone. Only 13.5% of patients treated with this DHE regimen required narcotics at the end of the study for relief of pain, compared to 45% of migraine headache patients seen concurrently in the same emergency department who were not enrolled in the study. We conclude that treatment with intravenous prochlorperazine and DHE is a safe and effective treatment and a useful alternative to narcotics.