Previous work from this laboratory has demonstrated that the colon, particularly the left colon, is the major site of persistent postoperative ileus after both minimal and more extensive abdominal operations. Inhalation anesthetics have been implicated in the past as a possible cause of altered postoperative bowel function, but direct evidence of such a role in postoperative ileus is lacking. In this investigation, the effects of three inhalation anesthetic agents, halothane, enflurane, and nitrous oxide, on contractile function of the right and left colon were investigated in monkeys. Enflurane and halothane administration caused cessation of contractions in both the left and right colon; suppression of motor activity continued throughout the period of anesthetic administration. Recovery of normal contractile function occurred relatively promptly after cessation of anesthesia with these drugs. Return of normal contractions was more prompt in the right than in the left colon. Administration of nitrous oxide was not associated with significant suppression of contractile function of either the the right or left colon. None of the three agents studied appear to have any role in typical postoperative ileus.