In a randomized, multi‐centre, double‐blind, placebo‐controlled, parallel group study, the efficacy of 100 mg oral sumatriptan was compared with that of placebo in the treatment of episodic tension‐type headache. The patients were recruited from the general population in the vicinity of the study centres, by randomly mailed invitations. One or more attacks were treated with sumatriptan by 54 patients and with placebo by 57 patients. A seven‐point verbal rating scale was used for hourly assessments of headache relief, 1–4 h after treatment According to the predefined primary end‐point of the study, which was moderate or complete relief of headache 2 and 4 h after treatment of the first attack, there was no significant difference between sumatriptan and placebo treatment Sumatriptan did perform statistically significantly better than placebo at some time points, but the effect was not considered clinically relevant We conclude that sumatriptan should not be used in treatment of tension‐type headache. The marked difference in effect of sumatriptan in treatment of migraine and tension‐type headache argues against the idea that migraine and tension‐type headache are part of a continuum of