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Lakes DHB Gastroenterology

Public Service, Gastroenterology & Hepatology (Liver)


This is a procedure which allows the doctor to see inside your large bowel and examine the surfaces directly to take biopsies (tiny samples of tissue) if needed.  Treatment of conditions can also be undertaken.

What to expect

The colonoscope is a flexible plastic-coated tube a little thicker than a ballpoint pen which has a tiny camera attached. You will be given a sedative (medicine that will make you sleepy but is not a general anaesthetic). The tube is passed into the rectum (bottom) and gently moved along the large bowel.  The procedure takes from 10 minutes to 1 hour and your oxygen levels and heart rhythm are monitored throughout.

The procedure is performed in a day stay operating theatre. 

Before the procedure

You will need to follow a special diet and take some medicine to make you go to the toilet and clear out your bowels (laxatives) over the days leading up to the test. Detailed instructions will be sent to you at the time.

Risks of a colonoscopy are rare but include:
  • bleeding if a biopsy is performed
  • allergic reaction to the sedative
  • perforation (tearing) of the bowel wall.

This page was last updated at 1:46PM on August 9, 2021.