Coming soon: AboutKidsHealth is getting a new look! Learn more Watch a video tour

Polyethylene Glycol (PEG) 3350

Your child needs to take the medicine called polyethylene glycol (say: pol-i-ETH-i leen GLY-kol) 3350 (PEG 3350). This information sheet explains what PEG 3350 does, how to give it, and what side effects or problems your child may have when he or she takes this medicine.

What is polyethylene glycol?

PEG 3350 is a medicine called a laxative. PEG 3350 is used to treat constipation.

You may hear PEG 3350 called by the name pegFlakes or Lax-A-Day. PEG 3350 comes in a powder form.

Before giving polyethylene glycol to your child...

Tell your doctor if your child has an allergy to polyethylene glycol.

Talk with the doctor or pharmacist if your child has any of the following conditions. Precautions may need to be taken with this medicine if your child has:

  • slow movement through the intestines or a blockage in the gastrointestinal tract
  • kidney disease

How should you give your child polyethylene glycol?

Follow these instructions when you give your child PEG 3350:

  • Give your child PEG 3350 for as long as the doctor or pharmacist tells you.
  • Give your child PEG 3350 at the same time every day, exactly as your child's doctor or pharmacist tells you. Pick a time that is easy for you so that you do not miss doses.
  • Measure out the dose using the special spoon or measuring cap that comes with the powder. A dose of 17 grams is equal to two rounded tablespoons of the powder. One rounded tablespoon is equal to two teaspoons.
  • Mix your child's dose of PEG 3350 powder in 120 mL to 240 mL of a suitable liquid (water, juice, or soda). Stir well. The powder will dissolve and your child should drink the entire dose, as tolerated, within a maximum of 20 minutes.

What should you do if your child misses a dose of polyethylene glycol?

  • Give the missed dose as soon as you remember.
  • If it is almost time for the next dose, skip the missed dose. Give the next dose at the regular time.
  • Do not give your child 2 doses to make up for 1 missed dose.

How long does polyethylene glycol take to work?

It may take 2 to 4 days before a bowel movement occurs.

What are the possible side effects of polyethylene glycol?

Your child may have some of these side effects while he or she takes PEG 3350. Check with your child's doctor if your child continues to have any of these side effects and they do not go away, or if they bother your child:

  • abdominal cramps
  • gas
  • bloating (fullness)
  • nausea

Call your doctor during office hours if your child gets:

  • a lot of diarrhea (loose, watery stools)
  • signs of dehydration, such as weakness, confusion, dry mouth, lack of tears when crying, decreased urination

What safety measures should you take when your child is using polyethylene glycol?

Contact your doctor if your child is still constipated after 1 week of receiving PEG 3350.

What other important information should you know about polyethylene glycol?

Give your child lots of fibre and fluids in his/her diet. High-fibre foods include fruits and vegetables, whole grain cereals, bran, and beans.

Keep a list of all medications your child is on and show the list to the doctor or to the pharmacist.

Do not share your child's medicine with others. Do not give anyone else's medicine to your child.

Keep PEG 3350 powder at room temperature in a cool, dry place away from sunlight. Do not store it in the bathroom or kitchen.

Do not keep any medicines that are out of date. Check with your pharmacist about the best way to throw away outdated or leftover medicines.

Keep PEG 3350 out of your child's sight and reach and locked up in a safe place. If your child takes too much PEG 3350, call the Ontario Poison Centre at one of these numbers. These calls are free.

  • Call 416-813-5900 if you live in Toronto.
  • Call 1-800-268-9017 if you live somewhere else in Ontario.
  • If you live outside of Ontario, call you local Poison Information Centre.

Disclaimer: The information in this Family Med-aid is accurate at the time of printing. It provides a summary of information about PEG 3350 and does not contain all possible information about this medicine. Not all side effects are listed. If you have any questions or want more information about PEG 3350, speak to your health care provider.​​

Jennifer Drynan-Arsenault, BSc, RPh, ACPR

Elaine Lau, BScPhm, PharmD, MSc, RPh