What is a colonoscopy?

A colonoscopy is a procedure that allows doctors to see the lower part of your child’s digestive system. This includes the rectum and large intestine (the colon).

Why is a colonoscopy done?

A colonoscopy allows doctors to investigate symptoms (such as bloody stool, anemia or abdominal pain) or check on existing conditions (such as ulcerative colitis or Crohn’s disease). A colonoscopy can also be done to enable the removal of polyps or to treat bleeding.

How is a colonoscopy done?

During a colonoscopy, a thin flexible tube with a camera on the end is inserted through the anus and up into the rectum and large intestine. The doctor will be look for changes in how the bowel (the inside of the intestine) looks, such as bleeding, inflammation or polyps. They will also collect small samples of tissue (called biopsies) for testing.

During a colonoscopy, a thin flexible tube with a camera on the end is inserted through the anus and up into the rectum to look at the large intestine (colon).

All children getting a colonoscopy will receive general anaesthetic. This means that your child will be given a medication so they will sleep through the procedure. If there is a family history of malignant hyperthermia or other reactions to anaesthesia, please let your nurse know before the procedure. General anaesthetics are safe, and are given by a specially trained doctor called an anaesthesiologist. The anaesthesiologist will meet with you before the procedure to explain how the anaesthetic is given and to discuss any possible complications.

Risks of a colonoscopy

Colonoscopy is a safe, low-risk procedure. However, you may experience the following side effects:

  • Small drops of blood in the stool for one to two days after the procedure
  • Nausea, vomiting or bloating for a few hours after the procedure
  • Irritation of the rectum

Very rarely, the following complications may occur:

  • Infection, in which case your child will be given antibiotics.
  • Heavy bleeding from the colon, which can often be treated immediately at the time of the colonoscopy, but which may require admission to hospital.
  • Tearing or perforation, in which a hole is caused in the wall of the colon. This may require surgery to fix. This is very rare, occurring in approximately one child out of 1000 children who have a colonoscopy.

If your child is at a high risk of infection, they may be given antibiotics preventively before the colonoscopy takes place. However, the likelihood of any of these complications occurring is small. If any of these complications occur, they are usually recognized before your child is discharged home.

You should contact your doctor or visit the Emergency Department if you notice these signs and symptoms after the procedure:

  • fever and/or chills
  • severe pain in the abdomen
  • bloody stools or black stools

Preparing for your colonoscopy

Your child must follow strict eating and drinking rules before the procedure. Your child’s stomach must be empty before a general anaesthetic. If the eating and drinking instructions are not followed correctly, for the safety of your child, the procedure may be cancelled when you get to the hospital. If your child has special needs during fasting, talk to your doctor to make a plan. If your child is on daily medications, make a plan with your doctor about which medications to take on the day of procedure and when to take them.

Please reschedule or cancel your appointment if your child:

  • Has a cough, cold, nasal congestion, vomiting or diarrhea, or if they are generally unwell
  • Has been sick with, or exposed to, chicken pox or tuberculosis in the past four weeks.

To be able to see the bowels properly during the colonoscopy, your child’s bowels need to be cleared of all stool. This is called “bowel prep”.

Bowel prep includes:

Time before the procedure


7 days before

Your child should stop taking iron supplements. Iron sticks to the bowel wall and may interfere with visibility.

3 days before

Your child should start a low residue/low fibre diet*

1 day before

Your child may have a light breakfast and light lunch** around noon. This will be their last meal until after the test.

Your child should only drink clear fluids.***

At 4 p.m., give your child their first dose of bowel-prep medication (e.g., PicoSalax) as recommended by your health-care provider.

Day of the procedure

Your child will take a second dose of bowel-prep medication once they arrive at the hospital for their colonoscopy. At this point, your child must walk around and move as much as possible. They should also drink plenty of clear fluids until 3 hours before the colonoscopy at which they should stop drinking clear fluids.

Your child’s bowel is clear when they have passed several watery stools that are clear or yellow. If the bowel-prep medication has not cleared the stools, your child may need to receive an enema.

*Foods to choose – low residue/low fiber diet: White bread, white pasta, white rice, plain cereal and crackers, skinless potatoes, chicken, turkey, fish, eggs, applesauce, melons, canned fruits (without the skin), ripe bananas, well-cooked vegetables, mayonnaise, mustard and plain desserts (vanilla wafers, sherbet, animal crackers).

*Foods that are not low residue/low fiber: Whole wheat bread, whole wheat pasta, brown or wild rice, granola, buckwheat and other high-fibre grains, tough meats (such as red meat), raw fruits with the skin, prunes and prune juice, raisins, berries, raw vegetables, nuts, seeds and popcorn.

**Examples of light breakfast/lunch: Any clear fluids, toast made with white bread (without butter), eggs (two maximum) scrambled without milk, 1.5 cups clear soup (not creamed) and 3 to 4 soda crackers, 2 ounces skinless turkey, chicken or fish and one medium potato without the skin.

***Examples of clear fluids: Drinks that are clear (NO red, blue or purple drinks) such as water, clear juices (apple, white grape), Pedialyte, Enfalyte, crystal/powder drinks), ginger alepopsicles and freezies. If you can see through it then it is a clear fluid.

***Fluids to avoid: Homemade juices, juices with pulp (such as orange juice), cider, milk, formula and Jell-O.

On the day of the colonoscopy

Arrive at the hospital early in the morning to register. After your child is registered they will receive an identification band and be shown to their room. It is important to bring your child’s health card or insurance information when you register.

The nurse will assess your child to be sure they are healthy enough for the test to be completed and the fasting rules have been met. Your child will then take another dose of bowel-prep medication, as described above. At the time of the procedure, your child will be taken to the procedure room or operating room for the colonoscopy. Your child will have an intravenous (IV) inserted once they are asleep.

After the colonoscopy

When the colonoscopy is complete, the doctor will speak with you regarding what they saw. The full results of the biopsies should be available a few weeks after the procedure. Expect to be at the hospital for at least two hours after the procedure to be sure your child wakes up safely.


Please contact your clinic nurse if you have not received the results within three weeks of the procedure.


Video on colonoscopy:

Key Points

  • A colonoscopy uses a camera to see the lower part of the digestive system to investigate symptoms or check on existing conditions.
  • Your child will need to follow a special diet starting seven days before their procedure and take two doses of bowel prep medication.
  • A colonoscopy is usually a low risk procedure.
  • Your child will be given a general anaesthetic.

Holly Norgrove, RN, BScN

Simon Ling, MBChB, MRCP(UK)​


At SickKids

SickKids will call to notify you of your child’s appointment details, as well as where and when to arrive. Colonoscopy procedures are usually performed on 4C, in the main hospital, on the 4th floor of the atrium (use the main elevators). Some cases are performed in the operating room, in the main hospital, on the 2nd floor of the atrium. Your doctor will decide where the colonoscopy will take place.

To change or cancel your appointment on 4C, please contact the clinic at 416-813-6583. For cases in the operating room, the procedure room nurses at 416-813-7004.

Sick Kids policy allows up to two adults to accompany a child for their procedure. The exception is a breastfeeding infant. If you have other children, please ensure you have made arrangements to have them stay at home on the day of the procedure.

For more information on fasting see Eating and drinking before surgery.

For more information on preparing your child for their procedure see Coming for surgery.

For information about getting to the hospital see Getting to SickKids