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HealthInfo Waitaha Canterbury


Colonoscopy is a procedure that lets doctors see inside your large bowel (also called large intestine or colon).

In a colonoscopy, a doctor passes a thin, flexible tube into your bottom and through to your large bowel. The tube is about the width of an index finger and has a tiny video camera at the end, which sends images to a screen so the doctor can see inside your bowel. The doctor can also take small samples of tissue if necessary.

Colonoscopies are done in hospital and you can usually go home the same day. You do not have to have a general anaesthetic but you're usually given a sedative to relax you so you do not feel much discomfort.

Your bowel needs to be completely empty before a colonoscopy. If you need to have one, you'll be given information about preparing your bowel, which involves taking laxatives on the day of your procedure or the day before. It's important to follow the instructions closely so the doctors can see inside your bowel clearly.

If you're having a flexible sigmoidoscopy, you will not need to do bowel preparation but you'll be given an enema before the procedure.

The video at the top of this page shows you what to expect if you have a colonoscopy at Christchurch Hospital.

Some people may have a CT colonogram instead of a colonoscopy. Your doctor will tell you if you're going to have this procedure.

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Written by HealthInfo clinical advisers. Last reviewed October 2020.

See also:

Colonoscopy & sigmoidoscopy if you have diabetes

Having an anaesthetic

Page reference: 20309

Review key: HICOL-20309