Records of all patients discharged with a diagnosis of migraine from 2 Danish neurological departments were examined to determine the incidence of drug abuse. These departments had fixed uptake areas with a population of approximately 500,000 during the 5 year study period (1-1-1976--31-12-1980). Patients were selected for detailed analysis if (1) they used morphinomimetic drugs once a month or more, (2) took 7 or more tablets of weak analgesics a day or (3) consumed more than 60 mg ergotamine a month. A total of 92 patients fulfilled these criteria, 27 only because of ergotamine overuse. Injections of morphinomimetic drugs were given once a week or more frequently to 32 patients. These patients also usually had an escalating consumption and were usually regarded as abusers by their doctors. During admission morphinomimetics were discontinued. None deteriorated, 1/3 remained unchanged whereas 2/3 improved. Thus 32 patients can be regarded as abusers of morphinomimetics which represents an annual incidence of 13 per million inhabitants. We caution against the use of morphinomimetics in migraine.