General care

• Maintain gentle oral hygiene with a soft toothbrush.
• Rinse several times daily with warm salt water.
• Avoid spicy, acidic, very hot, rough, or hard foods; avoid tobacco and alcohol.
• Drink adequate fluids and use soft, bland foods.
• Use paracetamol/acetaminophen or ibuprofen if suitable for you.

Pain relief

• Topical anesthetic gel or mouth rinse, such as lidocaine, can help before meals.
• Benzydamine mouth rinse/spray may reduce pain and inflammation.
• Protective oral gels or pastes can cover ulcers.

Aphthous stomatitis, or canker sores

• Topical corticosteroids are the usual first-line treatment, for example triamcinolone dental paste or a steroid mouth rinse, started early in an outbreak.
• Antiseptic mouthwash, such as chlorhexidine, can reduce secondary infection and may shorten episodes.
• Recurrent, severe, large, or persistent ulcers need medical or dental assessment. Iron, folate, vitamin B12 deficiency, coeliac disease, inflammatory bowel disease, Behçet disease, medicines, and immune problems may need exclusion. There is no permanent cure for recurrent aphthous stomatitis, but treatment reduces pain and duration.

Infectious causes

• Oral thrush/Candida: antifungal treatment such as nystatin or miconazole, plus cleaning dentures and removing them at night if relevant.
• Herpes-related stomatitis: early antiviral therapy may be appropriate in severe cases or in people at higher risk, prescribed by a clinician.
• Bacterial infection: antibiotics are not routine and should only be used when a clinician identifies a bacterial cause.

Denture stomatitis

• Treat Candida if present.
• Clean dentures daily, remove them overnight, and have ill-fitting dentures adjusted.
• Address smoking and poor oral hygiene.

Seek urgent care now if

• You cannot drink, show dehydration, have high fever, rapidly spreading mouth/skin/eye lesions, trouble swallowing or breathing, or severe pain.
• You are immunocompromised, receiving chemotherapy, or have a very young child with poor intake.
• An ulcer lasts more than 2 weeks, is hard or unexplained, or keeps recurring frequently. This needs examination to exclude a serious cause.

1. Recurrent aphthous stomatitis, canker sores
   • Milia et al., 2022, Recurrent aphthous stomatitis (RAS): guideline for differential diagnosis and management, European Journal of Paediatric Dentistry. Practice Guideline, Tier 6, PMID: 35274547.
   • Covers evaluation for alternative diagnoses and systemic contributors, plus stepwise local treatment. Although written for paediatric practice, its diagnostic framework is broadly useful.
   • Link: PubMed record
2. Cancer therapy-associated oral mucositis/stomatitis
   • MASCC/ISOO clinical practice guidelines, published 2020: Elad et al., Cancer. Practice Guideline with systematic-review basis, PMID: 32786044.
   • This remains the major evidence-based international guideline set for chemotherapy-, radiotherapy-, and transplant-related oral mucositis. It emphasizes structured oral care, prevention measures tailored to the cancer regimen, and adequate analgesia rather than routine antibiotics or corticosteroids for uncomplicated mucositis.
   • Link: PubMed record
3. Continuously maintained cancer-care guidance
   • The US National Cancer Institute’s clinician-facing Oral Complications PDQ summarizes management of treatment-related oral mucositis. It recommends atraumatic oral cleansing, lubrication, avoidance of spicy/acidic/hard/hot foods, and stepwise pain control, with treatment guided by severity and blood counts.

Recent supporting evidence, not formal guidelines

• Umbrella systematic review, 2026: Evidence-based recommendations for the treatment of recurrent aphthous stomatitis [PMID: 41626665]. It supports topical corticosteroids as a central conventional option and reviews approaches such as hyaluronic acid and low-level laser therapy.
• Systematic review/meta-analysis, 2025: laser therapy versus placebo for aphthous ulcers [PMID: 40560435].
• Systematic review/meta-analysis, 2025: lower-level laser therapy for minor recurrent aphthous ulcers [PMID: 41286369].

Practical interpretation

• Aphthous ulcers: first-line care is usually topical anti-inflammatory treatment, pain relief, and evaluation of frequent, severe, persistent, or atypical ulcers for nutritional deficiency, medicines, gastrointestinal disease, Behçet disease, immune disorders, or other oral mucosal disease.
• Cancer-treatment mucositis: follow the MASCC/ISOO or local oncology protocol, not a generic aphthous-ulcer regimen.
• Thrush, herpes, denture-related stomatitis, or drug reactions: need cause-specific treatment, so these guidelines should not be applied interchangeably.