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A colonoscopy is a test that uses a narrow, flexible, telescope with a camera called a colonoscope to examine the lining of your large bowel.


When is a colonoscopy recommended?

A colonoscopy can be performed as a screening test for bowel cancer or a diagnostic test following a consultation with your GP or specialist. Colonoscopy may be recommended for one or a combination of the following symptoms particularly in those aged 40 years or over:

  • Bleeding from your bowels

  • Change in the frequency or consistency of your stools

  • Anaemia (a stomach examination may also be recommended)

How do I prepare?

You will be given a strong laxative to take on the day or evening before your test. This is to clean out the bowel so that any problems can be identified. You will also be asked to reduce the 

fibre in your diet and avoid certain medications. You will be given clear instructions at the time your test is booked.



How is it performed?

The procedure lasts around 20-30 minutes but could take up to an hour if any treatments are required e.g removing a polyp. On arrival, you will be checked in by a nurse who will ask you to put on a hospital gown that opens at the back. You may be offered an injectable sedative and a painkiller to help you to relax and be as comfortable as possible during the procedure. An alternative to sedation is nitrous oxide (Entonox or "gas and air").   


You will be asked to lie on your left-hand side and bend your knees. The first step is a gentle finger examination by a gloved, lubricated finger. The colonoscope will be passed gently through your bowel.  Air will then be pumped into your bowel to inflate it slightly and give a better view of your bowel. Don’t worry if you pass wind -it is expected! 

Colonoscopy, bowel problems

What are the possible complications?

Colonoscopy is usually a safe procedure but the following complications could occur :

  • Excessive bleeding(particularly if a polyp has been removed)

  • Bowel damage: (more likely if  a polyp has been removed)

  • Risks of sedation: some patients are particularly sensitive to sedation and may experience breathing problems or low blood pressure. There are mesaes in place to deal with these problems

What happens after the test?

You will be about the results of your colonoscopy before you go home even if it is normal. If any further tests are required, they will be arranged and a further appointment will be made to discuss the results with you.

Once the nurse is satisfied that you have recovered from the procedure, you will be allowed home. You will be given information on how to get help if you feel unwell.

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