The hallmarks of acute mesenteric vein occlusion are postprandial pain and evidence of a hypercoagulable state. Acute mesenteric vein occlusion presents similarly to the arterial occlusive syndromes but is much less common. Patients at risk include those with paroxysmal nocturnal hemoglobinuria; protein C, protein S, or antithrombin deficiencies; or the JAK2 mutation. Thrombolysis is the mainstay of therapy; these lesions are difficult to treat surgically. Aggressive long-term anticoagulation is required.