THE OCCURRENCE of neuropsychiatric disorders following portacaval anastomosis is in the range of 25%.1 Some of these patients have no further difficulty after the frequently observed postoperative liver decompensation reverses. Of those patients who continue to show signs of ammonia intoxication, the majority can be controlled with protein restriction and antibiotic administration. There are occasional patients, however, who cannot be controlled by diet and drug therapy. In the past these patients have required continual nursing care and have pursued progressive courses of neurologic deterioration leading finally to death. Recently, in an attempt to reduce ammonia formation, which is believed to be instrumental in causing the cerebral changes in patients with chronic portal-systemic encephalopathy, colectomy or colonic exclusion has been performed. A patient treated successfully by subtotal colectomy is reported here, and the experience in the literature reviewed. Report of a Case A 56-year-old white woman had a history of