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Why it's done - Colonoscopy

Why a colonoscopy is done

A colonoscopy can be done to look for a number of things.

To check the cause of your bowel symptoms

A colonoscopy is often done to check what's causing your bowel symptoms, such as:

  • bleeding from your bottom or blood in your poo
  • diarrhoea or constipation that does not go away
  • losing weight or feeling really tired for no reason

Most of the time it will not find anything to worry about.

But sometimes it might find something that needs a closer look or further testing.

To check for growths in your bowels (polyps)

Lots of people have growths in their bowels (bowel polyps), and most of the time they're harmless. But they can sometimes become cancer, so if they're found they need to be checked.

They can be removed during the colonoscopy and tested.

Your results will tell you if you need any further tests or treatment.

To look for signs of bowel conditions

A colonoscopy can be used to look for bowel conditions like:

These conditions can be hard to diagnose, so you may also have other tests.

Page last reviewed: 14 November 2022
Next review due: 14 November 2025