Colonoscopy

What to expect

During the procedure, a flexible tube with a camera, called a scope, is inserted into your anus and carefully passed through the rectum and colon. This allows the gastroenterologist to look at the lining of your large intestine and capture images for examination. Sometimes, the terminal ileum, which is the last part of the small intestine, can also be examined.

A colonoscopy may also include taking a small tissue sample, called a biopsy, and removing polyps (non-cancerous clumps of cells).

Colonoscopies help screen for, diagnose and monitor several conditions, such as:

• Colorectal cancer
• Crohn's disease
• Ulcerative colitis
• Diverticular disease
• Bowel obstructions
• Intestinal bleeding

Before the colonoscopy, you will receive instructions on how to cleanse your colon. It is important to follow them carefully.

There are specialized colonoscopy procedures, such as:

• Flexible sigmoidoscopy: Examines the rectum and the lower part of the colon.  
• Pouchoscopy: Examines the inside of an intestinal pouch, usually for people who have had a proctocolectomy and now have a constructed pouch.  
• Ileoscopy: Used for people with an ileostomy. The scope is inserted into the stoma and moved into the lower part of the small intestine for the examination.

The type of sedative used for a colonoscopy may vary depending on your medical needs and preferences. It is important to arrange for someone to take you home after the procedure, because the sedative can affect your ability to travel safely. 

What to bring

• Health (OHIP) card or valid health-care coverage
• Someone to help you get home, because the sedation may affect your ability to travel safely

How to access our services

You need a referral from a health-care provider to be seen in Endoscopy. Visit our referral criteria for more information.