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Bowel polyps

Find out about bowel (colonic) polyps, which are small growths on the inner lining of the bowel. There are often no symptoms but should usually be removed.

About this information

This NHS content is written for people in England. Services, entitlements and contact routes may differ in other countries.

Symptoms of bowel polyps

Bowel polyps do not usually cause any symptoms, so most people with polyps will not know they have them.

They are often found during a colonoscopy, for example if you're being checked for another bowel condition, like bowel inflammation or cancer.

Rarely, larger polyps can cause symptoms such as:

  • a small amount of slime (mucus) or blood in your poo
  • bleeding from your bottom
  • a change in your normal bowel habits, such as diarrhoea or constipation
  • losing weight without trying

See a GP if:

  • you have slime (mucus) or blood in your poo for 3 weeks or more
  • your bowel habit is different to normal
  • you are constipated and it's not improving with treatment, or it happens regularly and lasts a long time
  • you've lost a noticeable amount of weight without trying

Try not to be embarrassed. The doctor or nurse will be used to talking about these symptoms.

Ask for an urgent GP appointment or get help from NHS 111 if:

  • you've had diarrhoea for more than 7 days
  • your poo is black or dark red
  • you have bloody diarrhoea

You can call 111 or get help from 111 online .

Go to A&E or call 999 if:

  • you're bleeding non-stop from your bottom
  • there's a lot of blood – for example, the toilet water turns red or you see large blood clots
Find your nearest A&E

Bowel polyps and bowel cancer

Polyps are usually harmless and do not become cancerous. But in a small number of cases a polyp can become cancerous over many years.

Bowel cancer screening can help find polyps that are more likely to develop into bowel cancer. These polyps are then removed.

Diagnosing bowel polyps

If your GP thinks your symptoms could be caused by bowel polyps, they may recommend a colonoscopy or a CT colonography.

Colonoscopy

A colonoscopy is where a long, thin flexible tube with a small camera at the end (a colonoscope) is passed into your bottom and guided up into your bowel to look for polyps.

A colonoscopy should not be painful, but can feel uncomfortable.

CT colonography

A CT colonography scan uses X-rays and a computer to create a detailed image of your bowel and show any polyps. You'll be given special liquid before the scan so that your bowel can be seen clearly.

Treatment for bowel polyps

Bowel polyps are usually removed while having a colonoscopy.

A wire loop that is part of the colonoscope will cut off (snare) or burn off (cauterise) the polyp. This is called a polypectomy and is painless.

Rarely, when there are lots of polyps or a polyp is very large, surgery may be needed to remove part of the bowel.

After treatment

After the polyp or polyps have been removed, they're sent to a lab to check if:

  • the polyp has been completely removed
  • there's any risk of it regrowing
  • there's any cancerous changes in the polyp

If there are cancerous changes in the polyp, you may need further treatment. Your specialist will advise you about this.

Causes of bowel polyps

The exact cause of bowel polyps is not known. It's thought they're 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're over 50 (around 1 in 4 people over 50 will have at least 1 polyp)
  • you have inflammatory bowel disease, which includes ulcerative colitis or Crohn's disease
  • you're overweight or smoke

Bowel polyps

Symptoms

Bowel polyps

Complications

Bowel polyps

Causes

Bowel polyps

Diagnosis

Bowel polyps

Medical treatments

Bowel polyps do not usually cause symptoms, but can cause mucus or blood in your poo, weight loss, diarrhoea or constipation.

There's a small risk of polyps turning into bowel cancer. Bowel cancer screening helps find polyps so they can be removed before becoming cancerous.

It's not clear what causes bowel polyps, but they may be more likely if you're over 50, smoke, have a bowel condition, or a family member has them.

Bowel polyps can be diagnosed using a colonoscopy, but most are found when looking at the bowel for another reason or during bowel cancer screening.

Bowel polyps are usually treated by removing them using a wire loop (polypectomy). Rarely surgery may be needed.

Content supplied by the NHS website

Content supplied by the NHS website, refreshed 19 August 2026. View the original NHS article ↗

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