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A colonoscopy is an exam that views the inside of the colon (large intestine) and rectum, using a tool called a colonoscope.
The colonoscope has a small camera attached to a flexible tube that can reach the length of the colon.
Your bowel needs to be completely empty and clean for the exam. A problem in your large intestine that needs to be treated may be missed if your intestines are not cleaned out.
Your health care provider will give you the steps for cleansing your bowel. This is called bowel preparation. Steps may include using enemas, not eating solid foods for 2 or 3 days before the test, and taking laxatives.
You need to drink plenty of clear liquids for 1 to 3 days before the test. Examples of clear liquids are:
You will likely be told to stop taking aspirin, ibuprofen, naproxen, or other blood-thinning medicines for several days before the test. Keep taking your other medicines unless your doctor tells you otherwise.
You will need to stop taking iron pills or liquids a few days before the test, unless your health care provider tells you it is OK to continue. Iron can make your stool dark black. This makes it harder for the doctor to view inside your bowel.
The medicines will make you sleepy so that may not feel any discomfort or have any memory of the test.
You may feel pressure as the scope moves inside. You may feel brief cramping and gas pains as air is inserted or the scope advances. Passing gas is necessary and should be expected.
After the exam, you may have mild abdominal cramping and pass a lot of gas. You may also feel bloated and sick to your stomach. These soon go away.
You should be able to go home about 1 hour after the test. You must plan to have someone take you home after the test, because you will be woozy and unable to drive. The nurses and doctors will not let you leave until someone arrives to help you.
When you are home:
Colonoscopy may be done for the following reasons:
Normal findings are healthy intestinal tissues.
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National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines): Colorectal cancer screening. Version 2.2013. Available at: http://www.nccn.org/professionals/physician_gls/pdf/colorectal_screening.pdf. Accessed October 24, 2013.
Pasricha PJ. Gastrointestinal endoscopy. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 136.