Severe ischaemia of the left upper limb developed in a 42-year-old woman (who had suffered from migraine since the age of 6 years) after the intake of 12 mg ergotamine tartrate (six suppositories of Cafergot within 5 hours). The left hand became very painful and pale with loss of touch sensation, and she could not move her fingers. Selective catheter angiography demonstrated typical signs of vascular ergotism: arterial spasms, corkscrew-like collaterals and segmental arterial occlusions. The patient's symptoms began to improve 10 minutes after starting an intraarterial infusion of prostaglandin E1 (0.34 ng/kg per min over 10 hours). Sensory function in the fingers was restored after 24 hours and reactive hyperaemia had occurred. Radiological examination after 48 hours showed complete recovery. This case emphasizes the need for obtaining an exact history regarding drug intake in any case of acute peripheral vascular disorder, but especially if there is no pointer to arterial thromboembolism. Angiography is of value in the differential diagnosis of suspected ergotism. Intraarterial infusion of prostaglandin E1 has few side effects and is immediately effective.