AbstractProstaglandin E1has a strong vasodilator effect, it inhibits the aggregation of platelets and improves the microcirculation. The hormone is synthesized from arachidonic acid and 80–90 per cent is eliminated in the first transit of the pulmonary circulation. From 1 January 1978 to 30 June 1981 100 patients suffering from inoperable occlusion of the arteries of the lower limbs and facing amputation were treated with intra‐arterial PGE1by prolonged perfusion over an average period of 34 days. PGE10·1–0·2ng kg−1body weight min−1was administered. Forty‐even of 100 legs were saved; 22 of 29 patients suffering from diabetes requiring insulin had to undergo amputation, but only 1 of 18 patients suffering from thromboangiitis obliterans had to have an amputation. The results of treatment in the 52 cases of uncomplicated arteriosclerosis lie in between, with 18 amputations. The complications that followed treatment were haemorrhage, arterial thrombosis, infection and myco