

For the procedure, you will lie on your left side on the examining table. You will be given pain medication and a mild sedative to keep you comfortable and to help you relax during the exam. The physician will insert a long, flexible, lighted tube into your rectum and slowly guide it into your colon. The tube is called a colonoscope (koh-LON-oh-skope). The scope transmits an image of the inside of the colon onto a television or computer monitor, so the physician can carefully examine the lining of the colon. The scope bends, so the physician can move it around the curves of your colon. You may be asked to change position occasionally to help the physician move the scope. The scope also blows air into your colon, which inflates the colon and helps the physician see better.

If anything unusual is in your colon, like a polyp or inflamed tissue, the physician can remove it or a piece of it using tiny instruments passed through the scope. That tissue (biopsy) is then sent to a lab for testing. If there is bleeding in the colon, the physician can use the scope to pass a laser, heater probe or electrical probe, or inject special medicines, to stop the bleeding.


Colonoscopy takes 30 to 60 minutes. The sedative and pain medicine should keep you from feeling much discomfort during the exam. You will need to remain at the physician's office for 1 to 2 hours until the sedative wears off.


Preparation for a Colonoscopy

Your colon must be completely empty for the colonoscopy to be thorough and safe. To prepare for the procedure, you may have to follow a liquid diet for 1 to 3 days beforehand. A liquid diet means fat-free bouillon or broth, gelatin, strained fruit juice, water, plain coffee, plain tea, or diet soda. You may need to take laxatives or an enema before the procedure. Also, you must arrange for someone to take you home afterward; you will not be allowed to drive because of the sedatives. Your physician may give you other special instructions.

National Digestive Diseases Information Clearinghouse

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Bethesda, MD 20892-3570






The National Digestive Diseases Information Clearinghouse of The National Institutes of Health. "Colonoscopy." NIH Publication No. 98-4331. July 7, 1998.

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