Pharmacist prescribing · Mississauga

Canker sores? We can help them hurt less.

Canker sores are small, but they can make eating, drinking and talking miserable. A pharmacist can confirm what it is and prescribe something to help.

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What are canker sores?

Canker sores (aphthous ulcers) are small, shallow sores inside the mouth: on the inner cheeks, lips, tongue or gums. They’re usually round or oval, white or yellow in the middle with a red edge.

They aren’t contagious and aren’t caused by the cold sore virus. Common triggers include a bite or scrape inside the mouth, stress, certain foods, and some toothpastes. Most heal on their own in 1 to 2 weeks.

Listed in Ontario’s minor ailments program as: Oral aphthae (canker sores).

Common symptoms

  • One or a few small, painful sores inside the mouth
  • White, grey or yellow centre with a red border
  • Stinging when you eat salty, spicy or acidic food

How a Kennedy pharmacist can help

Your pharmacist will look at the sore, ask how often you get them, and check for anything that suggests something other than a canker sore.

They may prescribe a corticosteroid dental paste that sticks to the sore, calms the inflammation and helps it heal. We can also suggest over-the-counter gels that numb the pain while you eat. We’ll also suggest ways to avoid triggers, like switching to a gentler toothpaste.

If we think you’d be better served by a doctor, we’ll tell you, and help you figure out where to go.

Medicines a pharmacist may consider

  • Triamcinolone dental paste (Oracort)a corticosteroid paste that sticks to the sore, calms it and helps it heal

Your pharmacist chooses based on your symptoms, age, pregnancy, allergies and other medications, so not every option is right for everyone. Brand names are examples. We often use the generic version, which works the same and usually costs less.

What it costs

The assessment is free with a valid Ontario health card. It’s paid for by the province, just like a visit to your doctor.

If you’re prescribed something, the medicine is paid for like any other prescription: through your drug plan, the Ontario Drug Benefit (65+ and other eligible people), OHIP+ (under 25 without a private plan), or out of pocket.

No Ontario health card? Text or call us first and we’ll tell you the fee before we start.

When to see a doctor instead

See your family doctor, a walk-in clinic or a nurse practitioner if:

  • A sore is larger than about 1 cm, or lasts more than 2 weeks
  • You get them very often, or several at once
  • You also have a fever, rash, eye problems or tummy issues
  • It’s so painful you can’t drink enough fluids
  • You have a sore that isn’t painful but won’t heal (have a dentist or doctor check it)

Not sure? Call Health811 (dial 811) any time to speak with a registered nurse, free.

Canker sores: common questions

Can a pharmacist prescribe for canker sores in Ontario?

Yes. Canker sores were added to Ontario’s minor ailments list in October 2023. The assessment is free with a valid Ontario health card.

Are canker sores contagious?

No. Unlike cold sores, canker sores are not caused by a virus and can’t be passed to others.

How long do canker sores last?

Most heal on their own in 7 to 14 days. Treatment can make them less painful while they heal. See a doctor or dentist if one lasts longer than 2 weeks.

This page is general information, not a diagnosis. A pharmacist will assess you before recommending any treatment.

Start with a quick text.

Tell us what’s going on and we’ll let you know if a pharmacist can help, usually the same day.