What you need to know before you have a colonoscopy

How to prepare for a colonoscopy

For a colonoscopy, your colon has to be completely empty. You need to follow a special liquid diet (broth, bouillon, clear beverages) for a few days before the test. The evening before the test, you will take a laxative. You can do your regular activities the day before your colonoscopy, but keep the evening free as you will need to go to the bathroom a lot.

The clinic will give you instructions about:

  • which medications you should stop taking
  • which laxative to take
  • what foods you can eat and beverages you can drink

Follow the instructions carefully.

On the day of your colonoscopy

  • Do not wear any jewellery or take valuables to the clinic with you.
  • Bring someone with you. You will receive sedatives during the colonoscopy. You will not be allowed to drive home.

What you can expect on the day of the test

Just before the colonoscopy, you will be:

  • asked to sign a consent form
  • able to ask questions
  • given a sedative to help you relax

During your colonoscopy

info icon During your colonoscopy
A biopsy removes a small piece of tissue from an area of concern in the body. A pathologist examines the tissue sample under a microscope to see if there are cancer cells in the tissue.
  • You will lie on your side.
  • The doctor will gently pass a thin flexible tube (a colonoscope) into your rectum through your anus.
  • Your colon will be inflated with air so the doctor can see the colon better.
  • You may feel some discomfort, but you should not feel any pain.
  • If polyps are found, the doctor may remove them.
  • The doctor may take biopsies if any abnormal areas are found in your colon.
  • The test will take approximately 20 to 30 minutes.

After your colonoscopy

  • You will be taken to the recovery room. You will stay in the recovery room for about 1 hour.
  • A nurse will monitor you closely.
  • Once the effects of the sedation wear off, you will be allowed to go home. Someone should accompany you.

Possible side effects

info icon For 24 hours after the test:
● Do not drive.
● Do not drink alcohol.
● Do not make important decisions or do anything that needs complex thought.
  • You may feel bloated and have cramps from the air in your colon. This will disappear as you pass the gas. Gradually increase your activities, such as walking, to help pass the gas.
  • You may have small amounts of blood in your stool, especially if you had a biopsy or had a polyp removed.
  • You might not have a bowel movement for a day or 2. Eat your normal diet.


Last updated: March 17, 2017