Oral rehydration therapy (ORT) by the enteral route was compared with intravenous ORT in a group of patients undergoing cholecystectomy. Rehydration was successfully accomplished in both groups; however, enteral rehydration was more comfortable, more economical, and caused fewer complications than the intravenous infusion. When the study was expanded to patients undergoing colonic surgery, the results were encouraging; enteral ORT in patients undergoing gastric or duodenal surgery was less successful.