A patient with recurrent episodes of consciousness disturbance following partial gastrectomy is presented. Angiographic examination revealed a great portasystemic shunt, which probably developed following the postoperative splenic vein thrombosis. This is suspected a rare cause of the condition. In chronic liver disease, recurrent encephalopathy which is caused by portasystemic shunt is well known as one of the most frequent complications. It is very uncommon in adults, however, when the liver is not concerned in the shunt formation. In the present paper the authors report an unusual case of recurrent consciousness confusion which is due to the great portasystemic shunt probably caused by postgastrectomy splenic vein thrombosis.