Canker sore treatment: fast relief at home and when to see a pro

Canker sores (aphthous ulcers) are small, painful ulcers inside the mouth. They’re not contagious, but they can make eating and talking miserable. The good news: simple home care helps most cases, and there are clear clues for when to get medical help.

Background & common issues

What they are. Round or oval ulcers with a red halo and pale center, on non-keratinized areas like the inside cheeks, lips, tongue, or floor of mouth NIDCR – nih.gov.

How common. Recurrent aphthous stomatitis affects up to about one in four people worldwide; most cases are minor and heal within roughly two weeks StatPearls – nih.gov.

“Topical corticosteroids are the first line of treatment for managing recurrent aphthous stomatitis; a short course of systemic steroids is reserved for severe cases.” — MC Plewa, MD, clinical summary, StatPearls NIH/NCBI Bookshelf.

Care framework: step-by-step

Key terms

• Aphthous ulcer (canker sore): a painful, shallow ulcer inside the mouth; not caused by herpes virus.
• Topical anesthetic: numbing gel or liquid (for example, benzocaine) used briefly to reduce pain.
• Topical corticosteroid: anti-inflammatory gel/paste (for example, fluocinonide in dental paste) applied thinly to calm inflammation.
• Chlorhexidine rinse: antimicrobial mouthwash sometimes used to reduce secondary infection and help healing.

At-home quick relief (most cases)

1. Rinse gently with salt water (½ teaspoon salt in a cup of warm water) up to several times daily MedlinePlus – Mouth sores.
2. Cool it: apply a cold compress outside the mouth for short intervals to reduce pain.
3. Spot-treat pain with a thin layer of an over-the-counter anesthetic or protective paste.
4. Reduce inflammation: consider a thin layer of topical corticosteroid gel/paste as directed; many people find this shortens pain days StatPearls – nih.gov.
5. Keep food gentle: favor soft, cool foods; avoid spicy, acidic, or sharp-edged foods that sting MedlinePlus – Canker sore care.
6. Protect the area: use a dental wax or bandage product if rubbing from braces or a chipped tooth is the trigger ADA MouthHealthy – mouthhealthy.org.

When to see a clinician

• Sores last beyond about two weeks, are unusually large, or recur continuously.
• Pain prevents eating or drinking, or you develop fever or swollen glands.
• You have frequent outbreaks plus fatigue, bowel changes, or other systemic symptoms (screening for deficiencies or conditions may be useful) StatPearls – nih.gov, NIDCR – nih.gov.

Clinical options your dentist may use

• Prescription topical corticosteroids or dexamethasone mouth rinse for short courses.
• Chlorhexidine mouthwash to lower bacterial load and support healing.
• Short systemic corticosteroid for severe major ulcers, after evaluation of risks and benefits StatPearls – nih.gov.
• Consider: if sores are constant or severe, clinicians may check iron, folate, and vitamin B12, or look for gastrointestinal or autoimmune causes StatPearls – nih.gov.

Tips & common mistakes

• Switch toothpaste if your brand contains sodium lauryl sulfate; some people report fewer sores after switching.
• Avoid scraping or popping the ulcer; this slows healing and increases infection risk.
• Mind abrasives: go easy with strong mouthwashes that sting or dry the mouth; consider alcohol-free formulas NIDCR – Dry mouth.

FAQ

Are canker sores contagious?

No. They are not caused by herpes viruses and do not spread by contact NIDCR.

What triggers them?

Common triggers include minor mouth trauma (biting, braces), stress, certain foods, and sometimes low iron or B-vitamins. A clinician can help check for underlying issues if outbreaks are frequent StatPearls.

Do supplements or honey work?

Some small studies suggest benefits for specific products, but evidence is mixed. Core care still focuses on pain control, gentle hygiene, and short courses of clinician-directed medications when needed Cochrane Library.

Safety

• Topical anesthetics: use sparingly and exactly as labeled; avoid in young children who may swallow excess.
• Corticosteroid pastes/rinses: short courses only, and stop if you notice white patches suggestive of oral thrush; tell your clinician about all medicines you use StatPearls – nih.gov.
• Red flags: persistent mouth ulcers, weight loss, or unexplained lumps require prompt evaluation.

Sources

• Canker sore: care and treatment – MedlinePlus (nih.gov)
• Fever blisters vs. canker sores – National Institute of Dental and Craniofacial Research (nih.gov)
• Recurrent aphthous stomatitis – StatPearls, NCBI Bookshelf (nih.gov)
• Systemic interventions for recurrent aphthous stomatitis – Cochrane Library
• Canker sores – American Dental Association (mouthhealthy.org)