Digestive Disorders Health Center

The Basics of Colonoscopy

Colonoscopy is an outpatient procedure in which your large bowel (colon and rectum) is examined.

Your doctor may perform the procedure to diagnose and treat, when possible, certain diseases of the lower gastrointestinal (GI) tract, which includes the rectum and colon.

	Colonoscopy Animation

A colonoscopy may be used to screen for colon cancer and evaluate many problems, including:

• Abdominal pain
• Anemia (low red blood cells)
• Blood in the stool
• Change in bowel habits
• Unexplained weight loss

Colonoscopy is often used to treat certain conditions:

• Bleeding from diverticula or other lesions can be treated by injecting medicine around them or by applying heat to cauterize -- or seal -- them.
• Polyps, some of which may be cancerous, can be removed using a lasso-like device through the colonoscope.
• Narrowed areas or strictures can often be dilated using a balloon.

How Do I Prepare for a Colonoscopy?

Before a colonoscopy, let your doctor know about any special medical conditions you have, including:

• Pregnancy
• Lung conditions
• Heart conditions
• Allergies to any medications
• If you have diabetes or take medications that may affect blood clotting. Adjustments to these medications may be required before the colonoscopy. Never stop taking any medication without first consulting your doctor.

You may need to take antibiotics before the colonoscopy if you:

• Have an artificial heart valve
• Have ever been told you need to take antibiotics before a dental or surgical procedure

To prepare for the test, your doctor will prescribe dietary modifications. You may be asked to limit or eliminate solid foods for a few days before the colonoscopy. You will also be asked to take laxatives by mouth to clean out the colon.

Along with the dietary changes, your bowel must be further cleansed in order for colonoscopy to be successful. Enemas or a special laxative drink may be given before the procedure. Follow your doctor's instructions on how to prepare for your colonoscopy. 

Make sure you arrange for a driver to bring you home after a colonoscopy. Because you receive sedating medication during the procedure, it is unsafe for you to drive or operate machinery for about 8 hours after the procedure.