Thrombosis of the splenoportal axis not associated with liver cirrhosis or tumoral disease is the second cause of portal hypertension in the western world. In up to 60% of cases, an underlying systemic prothrombotic disorder can be identified as an etiological factor. One third of cases are caused by local factors and the coexistence of several entities is not unusual. Therefore, an etiologic diagnosis is essential in these patients. Early anticoagulation therapy in the acute phase of thrombosis of the splenoportal axis significantly affects the probability of recanalization and consequently the prognosis of these patients. In the chronic phase of splenoportal thrombosis (or portal cavernoma), the symptoms are caused by the complications of established portal hypertension. To date, anticoagulation therapy is limited to patients in whom an underlying prothrombotic disorder has been demonstrated. (C) 2009 Elsevier Espana, S.L. All rights reserved.