BACKGROUND:Gastrointestinal paralysis after abdominal surgery has long troubled both patients and surgeons. Gastrointestinal side effects still constitute a major drawback in the acute use of opioids. Choice of postoperative analgesia may affect the rate of recovery of gastrointestinal function. The purpose of the present study was to investigate the influence of intravenous and epidural morphine on recovery of bowel function and pain by measuring intestinal motility and the visual analogue scale after colon surgery. METHODS: Twenty patients undergoing colon surgery used postoperative pain contol. Patients were allocated to receive either IV PCA (patient-controlled analgesia) with morphine or CEA (continuous epidural analgesia) with 0.1% bupivacaine-0.04% morphine. Patients were assessed for pain with a visual analogue scale, and for side effects at 1, 6, 12, 24, 48 hours postoperatively. Arterial blood samples for the measurement of blood gas and plasma concentration of morphine were taken. The time to first postoperative passage of flatus and feces, length of nasogastric therapy, time to liquid, soft and solid food intake, daily and total morphine requirement and length of hospital stay were recorded. RESULTS: There were no significant differences in bowel movement outcome except in length of nasogastric therapy, but the CEA group had significantly lower pain scores and required fewer days of nasogastric therapy when compared with the IV PCA group. CONCLUSIONS: These observations indicate that IV PCA with morphine and CEA can be used to relieve postoperative pain without prolonging the recovery of bowel movements, but CEA with bupivacaine and morphine constitutes an effective means of analgesia.