In 1976, 310 patients attended the Princess Margaret Clinic for treatment of an acute headache. 90% were either symptom-free or had only slight residual headache after 4 h. The treatment given was metaclopramide and an effervescent analgesic. 69% of patients had some form of sedation and 10% ergotamine tartrate. Those patients who had treatment between 6 and 12 h following the onset of an attack had significantly fewer attacks in the next 7 days. Patients who slept during an attack, with a sedative where indicated, recovered more quickly than those who did not sleep. The depth of sleep did not affect the rate of recovery. A higher percentage of patients with migraine compared with those with tension headache were either symptom-free or had only slight residual headache on leaving.