this is a cleansing of the bowels prior to going into hospital for treatment, so that any treatment can be carried out in safety. It involves changing your diet for a day or two before treatment, and you are given various concoctions to purge your system completely. It is not a pleasant procedure, but does ensure the best outcome for your surgery to be done in safety and minimize any risk of infection This is a typical advice note from a GP/Doctor: Bowel Prep- The process of cleaning the bowel of any solids prior to the examination of the bowel or bowel surgery. You may continue with your regular diet through the evening 2 days before your surgery. On the morning before your scheduled procedure begin a clear liquid diet only (broths and light soups are fine) At 9:00 AM on the day before surgery, begin drinking your ‘X brand' solution Drink all of the solution by noon if you can. You will shortly experience the desired results. By 6 PM, your stools should be very clear. You may drink clear liquids until midnight. Don't drink or eat anything after midnight on the day of surgery.