Why does surgery paralyze bowel movement?

Multifactorial: Post op constipation is attributed to decreased activity, dehydration, and the use of narcotic analgesics. So, prepare for upcoming surgery by eating right, drink plenty of water, and staying active. In our practice, for inpatients undergoing major procedures we use a medication (entereg) which prohibits the narcotics from interfering with bowel function. Ask your surgeon. Good luck.