Lidocaine and ketamine are non-opioid analgesics that have been shown to be safe and efficacious in low doses when combined with morphine for post-operative pain control. Since the addition of lidocaine or ketamine to a morphine PCIA regimen results in lower total use of morphine, and since lidocaine or ketamine does not slow peristalsis, , it is reasonable to expect that low-dose lidocaine or ketamine plus PCIA morphine will result in faster return of bowel function than PCIA morphine alone.