To the Editor.—The article "Abdominal Colectomy for Chronic Encephalopathy due to Portal-Systemic Shunt" by Picone et al (Archives 1983;118: 33-37) misses an important factor in that colonization of the small bowel follows colectomy in time. This reestablishes the precolectomy pattern of absorption of products of protein breakdown by bacteria. This has been shown to occur both experimentally and in reported clinical series. Retention of the ileocecal junction or formation of an ileal valve proximal to the ileosigmoid anastomosis helps prevent the problem. These procedures effectively prevent free reflux into the distal ileum and changes that occur in the disrupted junctional areas of the gastrointestinal tract, such as "gastricization" of the distal esophagus with esophageal reflux, "intestinalization" of the gastric mucosa with "alkaline reflux," and, now, colonization of the ileum with colonic reflux.