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Bowel polyps

Bowel polyps are small growths on the inner lining of the large intestine (colon) or rectum.

Bowel polyps are very common, affecting around 1 in 4 people at some point in their lives. They are slightly more common in men than women and are most common in people over the age of 60.

Some people develop just one polyp, while others may have a few.


Bowel polyps don't usually cause any symptoms. Most people with polyps won't know they have them. They are often picked up during screening for bowel cancer.

Some larger polyps can cause:

  • a small amount of slime (mucus) or blood in your poo (rectal bleeding)
  • diarrhoea or constipation
  • pain in your tummy (abdominal pain)

Bowel cancer risk

Polyps don't usually turn into cancer. But if some types of polyps (called adenomas) are not removed, there's a chance they may become cancerous. Doctors believe that most bowel cancers develop from adenoma polyps.

Very few polyps will turn into cancer, and it can take years for this to happen.

Because of the risk of bowel polyps developing into cancer, your doctor will always recommend getting polyps treated.

Read more about bowel cancer


Bowel polyps are usually found when your bowel is being looked at for another reason or during screening for bowel cancer.

If polyps are found, a colonoscopy or CT colonography is needed to view the whole of the large bowel and remove them at the same time.

Read more about bowel cancer screening


Doctors don't know the exact cause of bowel polyps. It is thought that they are caused by the body producing too many cells in the lining of the bowel. These extra cells then form into a bump, which is the polyp.

You may be more likely to develop bowel polyps if:

  • a member of your family has had bowel polyps or bowel cancer
  • you have a condition that affects your gut, such as colitis or Crohn's disease
  • you are overweight or smoke


There are several methods for treating polyps. The most common procedure is removing the polyp using a wire loop. This happens during a procedure called a colonoscopy.

The colonoscopy involves passing a flexible tube called a colonoscope through your bottom and up into your bowel. The colonoscope has a wire attached to it with an electric current through it. This wire is used to either burn off (cauterise) or cut off (snare) the polyp. Both of these methods are painless.

In rare cases, polyps may need to be treated by surgically removing part of the bowel. This is usually only done when the polyp has some cell changes, if it is particularly large, or if there are a lot of polyps.

After the polyp or polyps have been removed, they are sent to specialists in a laboratory. The laboratory will tell your consultant if:

  • the polyp has been completely removed
  • there is any risk of it regrowing
  • there is any cancerous change in the polyp

If there is a cancerous change in the polyp, you may need further treatment. This will depend on the degree and extent of change in the polyp. Your specialist will be able to advise you on this.

Monitoring bowel polyps

Some people with a certain type of polyp may be at risk of it coming back in the future (recurring).

This is uncommon, but means you'll need examining (by colonoscopy) at regular intervals of around 3 to 5 years. This is to catch any further polyps that may develop and potentially turn into bowel cancer.

Content supplied by the NHS and adapted for Ireland by the HSE

Page last reviewed: 30 May 2019
Next review due: 30 May 2022

This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.