AbstractPersistent diarrhea accompanied by water, electrolyte, and nutritional depletion and skin excoriation can occur following subtotal colectomy with ileoproctostomy. Attempting to improve the course of these patients, an experimental study using dogs was undertaken to evaluate the use of antiperistaltic ileal segment in the management of ileoproctostomy diarrhea. Subtotal colectomy with ileoproctostomy was performed in dogs. One animal died from weight loss and massive diarrhea with water and electrolyte depletion. The surviving dogs had water and electrolyte imbalance and lost an average of 30.6% of their body weight. A second group of animals was treated identically except that an antiperistaltic ileal segment was placed one foot proximal to ileorectal anastomosis. These dogs maintained their weight and electrolyte and water balance. The stools of these animals became solid, as opposed to the watery diarrhea of the animals with ileoproctostomy only. Ileoproctostomy diarrhea can be successfully controlled by the use of antiperistaltic ileal segment.