Constipation

Constipation is when stool builds up in the bowels and causes discomfort. It can happen even if a child or youth has a bowel movement every day. Constipation is common and rarely caused by a serious illness.

What you need to know

Constipation often develops over time and may take months to improve.
Stool buildup stretches the bowel, making it harder to empty.
Medication plus routine changes are usually needed.

Symptoms / Signs

Hard or painful stool
Very large stool
Stool type 1, 2, or 3 on the Bristol Stool Chart
Stomach pain or cramps
Trouble passing urine or frequent urination
Blood in stool
Stool leaking into underwear
Behaviour changes

Treatment / Procedure

Treatment usually requires medication for several months along with diet and routine changes.

Step 1: PEG3350 bowel clean out (3 days)

Use an oral laxative containing polyethylene glycol 3350 (PEG3350). Common brands include Lax-a-Day®, Restoralax®, Relaxa®, and Clearlax®.

Weight	Dose of PEG3350	Frequency
7–10 kg	2 tsp in 100 mL fluid	Twice a day for 3 days
11–13 kg	3 tsp in 150 mL fluid	Twice a day for 3 days
14–19 kg	4 tsp in 200 mL fluid	Twice a day for 3 days
20–34 kg	5 tsp in 250 mL fluid	Twice a day for 3 days
35–50 kg	5 tsp in 250 mL fluid	3 times a day for 3 days
50+ kg	10 tsp in 500 mL fluid	3 times a day for 3 days

Step 2: Bowel retraining routine (2 months)

Continue PEG3350 daily to prevent constipation and retrain the bowel.

Weight	Dose of PEG3350	Frequency
7–10 kg	2 tsp in 100 mL fluid	Once a day for 2 months
11–13 kg	3 tsp in 150 mL fluid	Once a day for 2 months
14–17 kg	4 tsp in 200 mL fluid	Once a day for 2 months
17+ kg	5 tsp in 250 mL fluid	Once a day for 2 months

Other things you can do at home to help

Give a healthy diet

Vegetables, fruits, and grains are good sources of fibre. The amount of fibre needed each day depends on your child's age. See Canada's Food Guide for the number of servings of vegetables, fruits and grains your child should have each day. Each meal and snack should include a fibre rich food. Increase fibre in your child's diet gradually.

Make sure to increase fluids at the same time.

Increase fluids

A 10 kg (22 lb) child needs 1 litre (4 cups) each day.
A 20 kg (44 lb) child needs 1.5 litres (6 cups) each day.
A 45 kg (99 lb) child needs 2 litres (8 cups) each day

Toddlers should have just 2-3 cups of milk each day. The rest of their fluid intake should be water. Limit juice, as it can cause cramping and gas.

Regular toileting

It can take weeks or months to train the bowel back to normal patterns. Take advantage of the body’s normal urge to empty after meals. 20-30 minutes after each meal at home, have your child sit on the toilet or potty for 1 minute each year of age (for example, 3 minutes for a 3-year-old). Give your child a foot stool if needed. This will make your child more comfortable and provide some support to help them let go of a bowel movement. Join your child to read a book together or chat and catch up! Younger children may like stickers on a chart for sitting in the toilet after each meal.

Keep a diary of:

how often your child has a bowel movement
the type of stool your child has (check the Bristol Stool chart and record the stool type)

More physical activity

Regular physical activity helps stimulate normal bowel function and keeps the bowel healthy. Children need at least one hour of moderate physical activity each day. For more information, check out Canada’s Physical Activity Guide to Healthy Living. Other things to consider

taking all milk or egg out of the diet for at least two weeks, in case there is an allergy

When to get help

Severe pain or pain lasting longer than 30 minutes
Fever
Vomiting
Weight loss
Waking from sleep to pass stool
Cracks in the skin around the anus
Rectal prolapse
Ongoing constipation after two weeks of treatment
Large amounts of blood in stool

Bristol stool chart

Need Help Right Now?

CHEO’s Emergency Department is open 7 days a week, 24 hours a day and cares for children and youth aged 0–18 years. Want to talk with someone? Call Health811 (dial 8-1-1) to speak with a nurse 24/7.

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Disclaimer

These resources are for educational purposes only. If you have questions, speak with your health care provider. Last updated: June 2026