For the colonoscopy procedure to be accurate, your colon must be well prepared. It must be clear of stool and fluids that obscure the view of the colon and rectal lining. Also, the colon contains bacteria and waste products that can cause infection if they leak into the abdomen during colon surgery. To prepare your colon, you will be asked to do the following at least 24 to 48 hours before the exam:
- Stop taking iron pills or medications containing iron, as iron can alter the color of your colon lining.
- Take laxatives and sometimes enemas that you are prescribed on the day prior to either procedure
- Avoid eating solid foods and opaque liquids at least 48 hours prior to either procedure. Only a soft or semiliquid diet (foods that are quickly and easily digested) should be consumed starting 48 hours prior to either procedure.
- Starting 24 hours prior to either procedure, drink only clear, nonalcoholic liquids such as black coffee, tea, water, or clear broth and juices. Eat only soft foods such as Jell-O — but not red Jell-O.
- Avoid liquids that are red in color, as they can look red in the colon and be confused with blood.
- Take a five-minute walk every 10 minutes during the time you're drinking the laxative, but stay near a toilet, as you may have frequent and urgent need to use the toilet.
- Drink plenty of liquids during the bowel preparation to avoid dehydration.
- Take nothing by mouth at midnight the night before either procedure.
If you unable to comply with this regimen, or if your bowel preparation is not working (you should have clear watery stool), it is necessary to inform the surgeon right away. If your bowel prep is not adequate, it may be unsafe to perform your colonoscopy or colon resection, and it may have to be postponed.