We describe the use of medication with symptomatic relief of migraine as specific indication by analysing prescription data from the entire Danish population in 1994 and 1995. The data for sumatriptan were analysed at the level of the individual user. We used aggregated data for ergotamine drugs. Sumatriptan constituted 46% of the total amount of defined daily doses (DDD) sold and 94% of the total pharmacy retail price expenses in the drug-group studied. In total, 43389 users of sumatriptan were identified who presented 340148 prescriptions, corresponding to 2.2 million DDD of sumatriptan. The quarterly consumption increased by 50% during the study period. Tablets accounted for 92% of consumption. The 1 year period prevalence of use of sumatriptan among persons 16 years and older was 7.8 per 1000 in 1995 with a female to male prevalence ratio of 3.8:1. Use was most common in the age interval 35-54 years. Regional differences in use, which were not large, were positively correlated to the degree of urbanization. The incidence of use of sumatriptan was estimated at 3.6 per 1000 person-years. The intensity of use of sumatriptan varied greatly with 1.1% of patients (n = 507) using 60 DDD or more within 30 days at some time during the observation period. Long-term high use of tablets was common in this group. We conclude that sumatriptan had a considerable impact on the treatment of migraine with prescription drugs in Denmark. The underlying reasons for high use of the drug in a smaller fraction of the patients deserve further study.