Colonoscopy is a very safe and popular procedure for colon cancer screening, diagnosis and treatment of a variety of large bowel diseases. Below are selected questions and answers with some modifications from ASGE and a youTube video from AGA.

Why is colonoscopy performed?

Colonoscopy is used to directly see the lining of the colon to look for conditions such as cancer, colitis (inflammation of the colon) and diverticular disease (small pockets on the colon). Colonoscopy may also be used to investigate unexplained diarrhea, bleeding and anemia. Sometimes colonoscopy is used to evaluate an abnormality seen on other imaging tests such as CT scans and barium studies.

What preparation is required?

Your doctor will tell you what sort of diet and cleansing routine to follow before the test. Your cooperation in this preparation will allow the gastroenterologist to get the clearest and most accurate views possible. In general, the "prep" involves drinking a special cleansing solution, along with plenty of clear fluids, and taking special laxatives by mouth. Be sure to tell your doctor about conditions such as diabetes, heart and/or kidney disease. You should plan your prep diet ahead of time and check with your doctor if you have any questions.

Can I take my regular medications?

Most medications can continue to be taken as directed, but some can interfere with the preparation or the examination. You should tell your doctor about all your medications, especially aspirin products, anti-inflammatory medications such as ibuprofen, pain medicines, blood thinners, insulin or iron supplements. Don't forget to mention "over the counter" supplements that you may be taking as well. You should also tell your doctor if you normally require antibiotics before dental procedures, since you may have the same needs before your colonoscopy.

Is colonoscopy painful?

A colonoscopy is a very comfortable exam because it is usually done with intravenous sedation. This means that you will be in a very sleepy state during the procedure. Most patients are not even aware that the procedure happened when they wake up.

Why is polyp removal (polypectomy) performed if found during the colonoscopy?

One of the most common uses of colonoscopy is for screening and prevention of colon cancer. Finding a potentially precancerous polyp is important as most cancers can be prevented by removing the polyp before it has a chance to become cancerous. Polyps vary in size from about the size of a pea to several inches and are usually harmless. However, some polyps can become cancerous and for this reason, they are usually removed during the colonoscopy. This procedure is called a "polypectomy." In most cases, your doctor cannot tell which polyps may eventually become cancerous, so the whole polyp, or at least a sample of it, needs to be examined under a microscope. The ability to safely and painlessly remove such growths before they become cancerous has made colon cancer one of the most preventable cancers in the world.

What happens after a colonoscopy?

Your physician will explain the results of the examination, but you will probably have to wait for the results of any biopsies. If you received sedatives during the exam, you will need to have a friend or relative take you home. Even if you feel alert after the procedure, your judgment and reflexes could be impaired for the rest of the day. Because your doctor used air to inflate the colon when looking at the lining of the colon, you might experience some cramping or bloating. This feeling should disappear once you start passing gas. Although you should be able to eat shortly after the examination, your doctor might restrict your diet and activities if a procedure, such as removing a polyp, was performed.

What are the possible complications or risks of colonoscopy?

Colonoscopy and the special techniques mentioned above are very safe when performed by specially trained doctors with experience performing these types of procedures. As with any medical procedure, even in expert hands, unintended events may happen and you need to be aware of the potential consequences.

There is a small risk of having a reaction to any of the drugs given during the exam. In most cases, medications are available to counteract these side effects. A rare complication is tearing or perforation of the lining of the intestine. Should this occur, surgery may be needed to seal the injury. Another risk is bleeding, usually at the site of a biopsy or polyp removal. Most cases of bleeding stop without treatment or can be controlled at the time of procedure.

What sort of things should concern me after the colonoscopy?

Although complications after colonoscopy are uncommon, it is important to be aware of early signs that something is wrong. You should not hesitate to contact your doctor up to two weeks after the colonoscopy if you feel abdominal pain, dizziness, fever/chills, or notice blood in your stools.

For more detailed information, please visit ASGE website at