How to Get Rid of a Canker Sore Fast: 5 Methods That Actually Work

If you have a canker sore right now, you want it gone — not managed, not numbed for an hour. The fastest way to get rid of a canker sore is a single-application chemical cautery treatment, which seals the ulcer, relieves pain immediately, and lets it heal under a protective barrier. Rinses and gels help too, but they work more gradually.

Left untreated, most canker sores (aphthous ulcers) heal on their own within about two weeks (Cleveland Clinic). The right treatment, applied early, can shorten that window and stop the pain right away.

Here are five methods, ranked by how fast they work, based on their mechanism of action and what users consistently report.

1. Chemical Cautery (Fastest — Single Application)

Chemical cautery is the fastest way to eliminate a canker sore. In a single application, it removes damaged tissue, kills bacteria, and forms a protective barrier over the wound. Pain relief is immediate and lasting because the barrier physically covers exposed nerve endings — it doesn't just numb them.

ORALMEDIC is the only over-the-counter chemical cautery treatment available in Canada. According to the manufacturer, its HYBENX Desiccation Shock Technology treats canker sores in one use, and users typically report complete healing within 3 to 5 days — a manufacturer-reported outcome, not a clinically established timeframe.

How to use it:

1. Dry the ulcer thoroughly with the included cotton bud (this is the most important step)
2. Snap the coloured ring on the applicator to release the gel
3. Roll the applicator across the entire ulcer surface for 5 to 10 seconds
4. Rinse your mouth with water and spit
5. Wait 30 minutes before eating or drinking

What to expect: A brief stinging sensation lasting 5 to 15 seconds during application — that's the active ingredient working on damaged tissue. The sting stops once the protective barrier forms. After that, pain relief is immediate and the ulcer is sealed.

Safety: This treatment is not recommended for children under 12, and should not be used by anyone with a sulphur allergy. Always follow the product instructions.

Best for: Severe or painful canker sores, recurring ulcers, and anyone tired of reapplying numbing gels several times a day.

2. Salt Water Rinse (Immediate Relief — Promotes Healing)

A warm salt water rinse is the most accessible canker sore remedy, and one dentists consistently recommend. Salt draws fluid from the ulcer through osmosis, which reduces swelling, and it creates an environment that's hostile to bacteria.

How to make it:

• Dissolve 1 teaspoon of table salt in 250 mL (1 cup) of warm water
• Swish around your mouth for 30 to 60 seconds, concentrating on the sore
• Spit — do not swallow
• Repeat 3 to 4 times daily

What to expect: Temporary stinging during the rinse, followed by reduced pain and swelling. A salt rinse won't eliminate the canker sore quickly, but it supports natural healing and keeps the area clean.

Best for: Mild canker sores, pain management between meals, and as a complement to other treatments.

3. Over-the-Counter Numbing Gels (Temporary Pain Relief)

Benzocaine-based gels like Orajel and Anbesol are the most widely used canker sore treatments in Canada. They temporarily block nerve signals at the application site, numbing the pain for 1 to 2 hours.

How to use them:

• Dry the area and apply a small amount of gel directly to the canker sore
• Reapply every 3 to 4 hours as needed (up to 4 times daily)
• Avoid eating or drinking for 15 to 30 minutes after application

What to expect: Quick pain relief within minutes that lasts 1 to 2 hours before wearing off. The ulcer itself heals at its own pace — benzocaine does not speed up healing.

Important note: Benzocaine carries an FDA warning about methemoglobinemia, a rare but serious blood disorder, and should not be used on children under 2 years of age (StatPearls).

Best for: Mild to moderate pain relief when you need temporary numbing — especially before meals or sleep.

For a detailed comparison of benzocaine gels vs chemical cautery, read our guide on benzocaine for canker sores.

4. Hydrogen Peroxide Rinse (Antiseptic — Promotes Healing)

A diluted hydrogen peroxide rinse helps clean the canker sore and reduce bacteria in the mouth. It works as a mild antiseptic and debriding agent, which can support faster healing.

How to use it:

• Mix equal parts 3% hydrogen peroxide and water (1:1 ratio)
• Dab directly onto the canker sore with a cotton swab, or swish gently for 30 seconds
• Spit thoroughly — do not swallow
• Use once or twice daily

What to expect: Mild bubbling or fizzing on the ulcer — that's normal, just oxygen being released as the peroxide reacts with tissue. Expect some temporary stinging. Regular use may shorten healing time modestly.

Best for: Keeping the ulcer clean and reducing infection risk, particularly for larger sores.

5. Anti-Inflammatory Products (Pain + Swelling Reduction)

Anti-inflammatory gels and rinses reduce the swelling around a canker sore, which is a major contributor to pain. Three common options:

• Benzydamine rinse (Tantum) — an anti-inflammatory mouthwash available in Canadian pharmacies. Rinse and gargle as directed. It provides both anti-inflammatory and mild pain-relieving effects.
• Corticosteroid paste (prescription) — your doctor or dentist may prescribe triamcinolone acetonide paste for severe or recurring ulcers. Apply directly to the sore to reduce inflammation.
• Ibuprofen (oral) — not a topical treatment, but over-the-counter ibuprofen reduces oral inflammation and pain systemically. Useful when a canker sore is making eating difficult.

Best for: Large, inflamed canker sores and situations where swelling is the primary issue.

Which Method Should You Choose?

Here's how the five methods compare at a glance:

You can also combine methods. A salt water rinse to keep the area clean, plus a single-application cautery treatment to seal the ulcer, is a practical combination.

Tips for Faster Healing

Whichever treatment you choose, these habits help canker sores heal faster:

• Avoid irritating foods — citrus, spicy foods, chips, and hard-edged foods will aggravate the sore. Read our guide on canker sores and diet for a full breakdown.
• Use a soft-bristled toothbrush — hard bristles can damage the sore and delay healing.
• Switch to SLS-free toothpaste — sodium lauryl sulphate (SLS) in most toothpastes irritates oral tissue. Learn more about this and other triggers in what causes canker sores.
• Treat early — the sooner you treat a canker sore, the faster it heals. Don't wait for it to get worse.
• Stay hydrated — a dry mouth slows healing and increases discomfort.

When to See a Doctor

Most canker sores are harmless and heal within about two weeks. A sore larger than 1 cm, or one that hasn't healed after two weeks, warrants evaluation by a healthcare provider (Cleveland Clinic). Also see a provider if:

• You get canker sores very frequently (more than 3–4 per month)
• The sore comes with fever, rash, or difficulty swallowing
• You have trouble eating or drinking due to pain

Persistent or unusually severe canker sores can sometimes indicate an underlying condition. Visit our FAQ for answers to common questions, or contact us if you need help.