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Colon Polyps

A colon polyp is a growth on the surface of the colon, also called the large intestine. Sometimes, a person can have more than one colon polyp. Colon polyps can be raised or flat.

Some colon polyps are benign, which means they are not cancer. But some types of polyps may already be cancer or can become cancer. Flat polyps can be smaller and harder to see and are more likely to be cancer than raised polyps. Polyps can usually be removed during colonoscopy—the test used to check for colon polyps.



Most people with colon polyps do not have symptoms. Often, people don’t know they have one until the doctor finds it during a regular checkup or while testing for something else.

But some people do have symptoms, such as

  • bleeding from the anus. The anus is the opening at the end of the digestive tract where stool leaves the body. You might notice blood on your underwear or on toilet paper after you’ve had a bowel movement.
  • constipation or diarrhea that lasts more than a week.
  • blood in the stool. Blood can make stool look black, or it can show up as red streaks in the stool.

If you have any of these symptoms, see a doctor to find out what the problem is.


The doctor can use one or more tests to check for colon polyps.

Barium enema. The doctor puts a liquid called barium into your rectum before taking x rays of your large intestine. Barium makes your intestine look white in the pictures. Polyps are dark, so they’re easy to see.

Sigmoidoscopy. With this test, the doctor puts a thin, flexible tube into your rectum. The tube is called a sigmoidoscope, and it has a light in it. The doctor uses the sigmoidoscope to look at the last third of your large intestine.

Colonoscopy. The doctor will give you medicine to sedate you during the colonoscopy. This test is like the sigmoidoscopy, but the doctor looks at the entire large intestine with a long, flexible tube with a camera that shows images on a TV screen. The tube has a tool that can remove polyps. The doctor usually removes polyps during colonoscopy.

Computerized tomography (CT) scan. With this test, also called virtual colonoscopy, the doctor puts a thin, flexible tube into your rectum. A machine using x rays and computers creates pictures of the large intestine that can be seen on a screen. The CT scan takes less time than a colonoscopy because polyps are not removed during the test. If the CT scan shows polyps, you will need a colonoscopy so they can be removed.

Stool test. The doctor will ask you to bring a stool sample in a special cup. The stool is tested in the laboratory for signs of cancer, such as DNA changes or blood.


Illustration of Polyp being removed by a Colonoscope.

In most cases, the doctor removes colon polyps during sigmoidoscopy or colonoscopy. The polyps are then tested for cancer.

If you've had polyps, the doctor may want you to get tested regularly in the future.



National Digestive Diseases Information Clearinghouse, USA.