Decrease Text SizeIncrease Text SizeFacebookTwitterYoutubeInstagramLinkedIn

image of kids smiling with text "programs and services" 

Caring for your child’s mouth and teeth during cancer treatment

 Click here to download a printable version of the information from this page. 

 Your child or teen will soon begin cancer treatment at CHEO. Chemotherapy and radiotherapy can affect the cells in the mouth. To prevent discomfort, infection and complications, it’s very important to take good care of the mouth and teeth through the course of cancer treatment.

All newly diagnosed patients should be seen by a dentist at CHEO before or soon after the start of treatment. We will :

  • Look for and treat any possible source of infection;
  • Remove orthodontic appliances and braces as needed;
  • Review toothbrushing and flossing technique;
  • Discuss diet and snacking;
  • Give your child or teen a proper sized toothbrush.

Tooth and mouth care during chemotherapy and radiation

  1. Brush teeth and tongue 2-3 times each day. Children 8 years and younger will need help from an adult to brush effectively. Use dental floss if your dentist tells you to.
  2. Take care of the toothbrush. Always let the toothbrush air dry after use. Replace the toothbrush every 2-3 months.
  3. Rinse after medications. Medication taken by mouth can contain sugars. Have your child or rinse with water after taking the medication. For very young children who can’t rinse or spit, wipe the teeth with a moist gauze or brush. Do not have your child or teen rinse after taking medication to treat yeast in the mouth.
  4. Stop using commercial mouthwash or rinses. Many have a high alcohol content, flavoring and color - ing agents that can dry and irritate the gums. Use baking soda mouthwash to help keep the mouth clean instead (recipe on the next page).
  5. Rinse or wipe after vomiting. Children and youth can rinse their mouths with baking soda mouthwash after vomiting. Stomach acids get in the mouth when a child or teen vomits. Baking soda mouthwash helps to neutralize any stomach acids so the mouth doesn’t get irritated.
  6. Check your child’s mouth often. Look for cankers (sores) and bruising. If your child’s mouth is too sore to brush or bleeds, use a baking soda mouthwash instead of brushing teeth with toothpaste.
  7. Apply moisturizing lotion or cream to lips. Use lanolin or water based products.
  8. Dental check ups every 6 months. Your child or teen should see a dentist every 6 months during active cancer treatments. Make sure your child or teen has a blood count done before a cleaning appointment. The blood cound must be high enough for us to go ahead with the cleaning. 

Baking soda mouthwash

Make this at home to help keep your child or teen’s mouth clean. It also helps to neutralize any stomach acids left in the mouth after vomiting.


  •   ¼ teaspoon (1mL) baking soda
  • 1 cup (250mL) tap water


  1. Stir the baking soda into the water until it dissolves.
  2. Pour the mixture into clean bottle with a lid. Store it at room temperature.
  3. Throw away any unused mouthwash after 24 hours.

How to use this mouthwash:

  • Make sure your child or teen doesn’t swallow the mouthwash.
  • Older children and teens can swish the mouthwash in the mouth for 30 seconds, and then spit it out.
  • If your child is too young to swish and spit, you can apply it to teeth, tongue and gums with a gauze, toothbrush or toothette.

Children and youth with mouth sores should avoid:

X   High acid foods like citrus fruits and juices, tomatoes, pineapple
X   Spicy foods
X   Crunchy, hard foods
X   Very hot food

Easy to eat foods

(for children and youth with mouth sores)

  • Milk shakes
  • Cooked cereals
  • Scrambles egg
  • Puréed foods
  • Soft fruits and vegetables
  • Custards, puddings, Jell-O®
  • Ice cream, frozen yoghurt
  • Ice chips

Numbers to know

CHEO Dental Clinic 613-737-2357

Oncology Clinic 613-737-2470

Take Action
Quick Links

Programs & Health Info
magnifying glass

Letter aLetter bLetter cLetter eLetter fLetter g Letter hLetter iLetter jLetter kLetter lLetter mLetter nLetter oLetter pLetter qLetter rLetter sLetter t Letter uLetter vLetter wLetter xLetter yLetter z
Zoomed image Close