This is a procedure which allows the endoscopist to see inside your large bowel and examine the surfaces directly and take biopsies (samples of tissue) if needed.  Treatment of conditions can also be undertaken.   The colonoscope is a flexible  soft coated tube a little thicker than a marker pen which has a tiny camera attached that sends images to a viewing screen. 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 procedure environment.    Before the procedure you will need to follow a special diet and take some laxative drinks to empty your bowel just prior to the appointment.  Risks of a colonoscopy are rare but include bleeding, allergic reaction to the sedative and perforation (tearing) of the bowel wall.