In a 39-year-old man there occurred, over a period of four years, mesenteric vein thrombosis with haemorrhagic infarction of the intestines, as well as multiple bleedings from oesophageal varices due to portal hypertension caused by portal vein thrombosis. Search for the cause of the thrombosis tendency revealed congenital protein C deficiency. Splenectomy and a disconnection operation were performed, followed by administration of anticoagulants. Since then the patient has been free of symptoms, and there have been no further variceal bleedings or thromboses.