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What Are Colon Polyps?

Colon polyps are growths that occur on the inner lining of the large intestine (colon) and usually protrude into the colon. Polyps form when the genetic material within the cells lining the colon changes and becomes abnormal. Normally, the immature cells lining the colon are programmed to divide, mature, and then die in a very consistent and timely fashion. However, the genetic changes that occur in the cells prevent them from maturing, and they don’t die. This leads to an accumulation of immature, genetically abnormal cells, which eventually results in the formation of polyps. The mutations may occur as a sporadic event after birth or they may be present from before birth.


Colon polyps often have no symptoms at all. You might not know you have a polyp until your doctor finds it during an examination of your bowel. But some people with colon polyps experience:

  • Rectal bleeding. This can be a sign of colon polyps or cancer or other conditions, such as hemorrhoids.
  • Change in stool color. Blood can show up as red streaks in your stool or make stool appear black. A change in color may also be caused by foods, medications and supplements.
  • Change in bowel habits. Constipation or diarrhea that lasts longer than a week may indicate the presence of a large colon polyp.
  • Iron deficiency anemia. Bleeding from polyps can occur slowly over time, without visible blood in your stool. Chronic bleeding robs your body of the iron needed to produce the substance that allows red blood cells to carry oxygen to your body. The result is iron deficiency anemia, which can make you feel tired and short of breath.


Doctors don’t know the exact cause of colonic polyps, but it’s certain that polyps result from abnormal tissue growth. The body gradually develops new healthy cells to replace old cells that are damaged. The growth and division of new cells is usually regulated. In some cases, new cells grow and divide before they’re needed. This excess growth causes polyps to form.

What Are the Risk Factors for Colon Polyps?

Risk factors for colon polyps include:

  • Family history of colon polyps
  • Diet high in red meats
  • Diet high in processed meats
  • History of inflammatory bowel disease
  • Older age


Your doctor is likely to remove all polyps discovered during a bowel examination. The options for removal include:

  • Removal with forceps or a wire loop (polypectomy). If a polyp is larger than 0.4 inches, a liquid may be injected under it to lift and isolate the polyp from surrounding tissue so that it can be removed.
  • Minimally invasive surgery. Polyps that are too large or that can't be removed safely during screening are usually removed laparoscopically, which is performed by inserting an instrument called a laparoscope into the bowel.
  • Colon and rectum removal. If you have a rare inherited syndrome, such as FAP, you may need surgery to remove your colon and rectum.

Colonic polyps are usually noncancerous and considered harmless. They often don’t cause any symptoms unless they’re extremely large. Removing polyps can reduce any related symptoms. It can also help prevent colon cancer from developing in the future. If you have polyps, you have a higher risk of developing more polyps in the future. Your doctor will recommend screening in three to five years.