Developed for the treatment of migraine, sumatriptan is an agonist of 5-hydroxytryptamine-1-receptors. Though a pressure sensation is a common complaint, significant ECG changes have not been reported after subcutaneous administration of sumatriptan. A case history is given where angina pectoris after sumatriptan self-administration was experienced on two occasions by a 61-year old man with a history of minor myocardial infarction--without post-infarction angina--two years previously. The angina after sumatriptan was accompanied on both occasions by significant ST-segment depression on ECG-monitoring. An extracranial vasoconstrictor action of sumatriptan in patients with ischaemic heart disease is suggested.