The poor prognosis of acute mesenteric artery occlusion can be improved by reaching a rapid angiographic diagnosis and by instituting treatment at an early stage. In addition to operative embolectomy, success may be expected from the use of urokinase infused superselectively into the superior mesenteric artery. This treatment is only likely to be successful if it is carried out within ten hours of the onset of clinical signs and symptoms. In patients with heart disease, angiography is recommended as soon as there is any suspicion of mesenteric occlusion, in order to confirm the diagnosis, localise the embolus and decide on the form of treatment. Urokinase treatment can be successful for embolic occlusion of the main branches or peripheral branches of the superior mesenteric artery. However, complete occlusion of the main superior mesenteric artery should be treated operatively. A contra-indication to urokinase therapy is occlusion due to infected emboli from an endocarditis.