This . This is a practice that is still debated in the surgical literature with surgeons and evidence on both sides. A bowel prep refers to cleaning out the colon of stool prior to an operation (usually on the bowels) or colonoscopy. There are a variety of bowel preps used and it often depends on the practice of your surgeon. Reasons given for doing a bowel prep include; avoiding contamination of the operative field, infection, better anastomosis (sewing bowel back together), better visualization (for colonoscopy), and more pleasant for operating surgeon. Reasons against include increased infection, complications related to the prep, patient comfort. There are a wide variety of bowel preps currently in use. Most involve drinking either a large volume of liquid or a small volume of a liquid which sucks fluid into the colon, both producing a watery diarrhea. Some bowel preps have included antibiotics with the thought it would lessen infectious complications. The data is not clear. Many surgeons simply recommend a clear liquid diet for a day or two before surgery to limit the stool in the colon. There are also studies which have shown bowel preps to be dangerous by either causing electrolyte imbalances, dehydration, or actually increasing infection. As of yet there is no right answer and usually the choice of bowel prep has to do with the surgeon and their experience as almost any can be supported by some evidence. Many surgeons do colorectal surgery with no bowel prep. A colonoscopy does require a bowel prep for visualization. Speak with your surgeon about their practice. By far the most comfortable for the patient is to consume clear liquids for a day or two.
Infection . Several studies have shown that a bowel prep, along with IV antibiotics at the time of surgery decrease the risk of post-operative infection.