Bowel Prep

Learn about how to prepare your body for a colonoscopy or other procedures.

Preparing for a colonoscopy is very important to ensure the procedure is successful.

Proper preparation involves cleansing the bowel thoroughly, which may also be necessary for other procedures such a virtual colonoscopy or gastrointestinal X-ray. If your bowel is not thoroughly cleaned out, the test may need to be repeated. 

Types of bowel prep

There are two main types of laxatives used to prepare the bowel for colonoscopies:

Polymer-based formulas: These usually come in a powder form that is mixed with water. They are effective and gentle on the inner lining of your bowel but require drinking large volumes of water and may lead to dehydration.

Saline-based formulas: Available in tablet form, these laxatives can be swallowed like a pill, making it easier to take. However, they may irritate the inner lining of the bowel in some people.

The choice of colonoscopy prep depends on your specific needs. 

How to prepare for a colonoscopy

One week before the test

  • Pick up the prescription for your bowel prep from a pharmacy.
  • Start following a low-fibre diet three or four days before your colonoscopy.
  • Follow any instructions you have been given about changes to any medication that you take. 

One day before the test

  • Eat a regular breakfast.
  • Have only clear liquids such as broth, black coffee or tea, strained juice or Jell-O up to six hours before your colonoscopy.
  • Follow the instructions regarding when and how to start taking your bowel prep laxatives The exact instructions will depend on what type of prep you are using and your scheduled colonoscopy time.
  • Give yourself ample time for your bowels to clear.

The day of the test

  • Do not eat anything.
  • You can drink clear liquids up to three hours before the colonoscopy.
  • Dress comfortably in loose-fitting clothes.
  • Bring someone to help you get home, as the sedation may impair your ability to travel safely.