Intravenous streptokinase infusions (100,000 units/h) have been used to treat 48 patients, with 50 episodes of acute limb ischaemia who were unlikely to benefit from a surgical approach. These included 17 acute thromboses, 14 late or distal emboli and 19 bypass graft occlusions. Overall, 17 (34 per cent) instances had complete lysis with reappearance of distal pulses and a further 28 per cent had clinical improvement without change in pulse status. Final outcome after 30 days was limb salvage in 60 per cent, amputation in 24 per cent and death in 16 per cent, but this was achieved after eight patients without lysis had vascular reconstructive surgery. Serious complications were infrequent, but included a fatal stroke, a haematemesis and two episodes of distal embolization. The outcome was not related to the duration of ischaemia or the site of occlusion. Lysis was more frequent with emboli (50 per cent) and graft occlusions (47 per cent) than arterial thromboses (6 per cent). Limb salvage was more likely in patients with no neurological deficit in the limb (70 per cent) than if a deficit was present (37 per cent). In conclusion, intravenous streptokinase produced a moderate benefit with low morbidity and has a role in acute limb ischaemia if surgery is inappropriate and intra-arterial lysis unavailable. In particular, selected patients with emboli or graft occlusions without a neurological deficit may be most suitable.