The case is a 69-year-old female who was admitted to our hospital under the diagnosis of normal pressure hydrocephalus secondary to cerebral infarction. V-P shunt was performed and postoperative course was uneventful until 7 months after operation, when she developed meningitis. Since then the level of consciousness became gradually worse down to akinetic mutism. Two years and 3 months after the operation she died of pneumonia. At autopsy peritoneal end of the shunt tube was found to have perforated the antero-inferior wall of the stomach. In this report, we discussed the mechanism of development of bowel perforation and preventive measures against this complication. As the causative factors it should be noted first that any foreign body in the peritoneal cavity is potentially able to cause bowel perforation. The second factor is the sharp tip of the peritoneal tube which perforates the bowel more easily. The third factor is the constant pressure at the same site of the bowel wall over a long period of time to cause necrosis of it. The fourth factor is the poor general condition of the patient with decreased resistance of the bowel wall against the foreign body. We therefore postulate for the prophylaxis and early diagnosis of this complication that a careful procedure with adequate tube is required at operation and a low grade fever and abdominal symptoms should not be overlooked afterward.