Postoperative ileus is a temporary paralysis of the gut following surgery. This disorder may be considered an inevitable consequence of surgery and it normally resolves within 2 to 3 days; however, it may resolve more slowly, causing discomfort, pain, and increased complications. According to one estimate, postoperative ileus prolongs hospitalization for approximately 5000 patients in the United States each year. Ileus is thought to be the result of many factors including physical manipulation of the gut, surgical stress, and inflammation. In addition, use of intravenous opioid pain killers likely has a substantial effect since opioid use is associated with decreased gut contractions. Opioid pain killers can induce or prolong ileus by binding to the mu-opioid receptors in the gut.