A colonoscopy is an examination to look at the lining of your whole large bowel, to see if there are polyps or a cancerous tumour within any part of it.

A long flexible tube (endoscope) with a bright light and a tiny camera on the end is inserted through your back passage and enables the doctor or nurse to get a clear view of the bowel lining. During the test, if the doctor sees anything that needs further investigation, photographs and samples (biopsies) can be taken. Simple polyps can be removed during a colonoscopy.

Preparing for a colonoscopy

Before having a colonoscopy, you may be seen by a specialist nurse or screening practitioner, who will explain what the procedure involves and outline the advantages and disadvantages of having it done. Alternatively, you may receive a telelphone call or instructions by post. You should be asked about any medical conditions (e.g. diabetes, kidney problems) to make sure that it is safe for you to have both the bowel preparation and the procedure.


In the two days before your colonoscopy you will need to start bowel preparation, which is a combination of medicine to drink and a temporary change in your diet. This is to make sure that your bowel is empty so that the doctor can perform the examination effectively, and get the best possible view of the bowel lining.

Making you comfortable

If you are anxious about the procedure, talk to the doctor or nurse about your concerns and ask whether you can have sedation. If you have problems lying flat, or being able to curl up on your side to have the test done, please do let the nurse know straight away, so that alternative arrangements can be made if necessary.


After a colonoscopy, the gas that was used to inflate the bowel can sometimes cause discomfort in your abdomen or shoulders for a short time. Peppermint chewing gum or warm peppermint tea, massaging your abdomen or walking about can help to relieve this and help the gas pass out of your body.