Before a colonoscopy, you will need to avoid solid food the day before (you can drink only clear liquids) and you will need to fast completely the night before. You’ll also have to take a liquid or pill laxative the night before (and possibly the morning of the exam, too) to clean out your colon. Your doctor might also recommend avoiding any medications.
Here are the instructions for different types of colonoscopy preparations:
During the colonoscopy, you’ll receive medication either in pill form or via a needle in your arm (IV) to sedate you and make you comfortable during the procedure. Then a long tube (colonoscope) is inserted into your rectum and colon. The tube has a light and camera so your doctor can see inside your colon on a monitor. To get clearer images, your doctor can pump air into your colon through the tube, which may cause some cramping. Your doctor can insert instruments through the tube to take tissue samples (biopsy) or to remove polyps and abnormal tissue.