Mouth Sores

What is it?

Oral ulcers can be classified as aphthous (canker sores — the most common, idiopathic, and non-contagious), herpetic (cold sores from HSV-1, occurring on lips/gums), or associated with systemic disease (Crohn's, Behçet's disease, celiac disease, IBD, neutropenia, or drug reactions). Recurrent aphthous ulcers affect up to 20% of the population. Persistent, non-healing oral ulcers in adults — especially those who smoke or drink alcohol — may represent oral cancer and require evaluation.

Common causes

When to see a doctor

• 1A mouth sore lasting more than 3 weeks without healing
• 2White or red patches in the mouth that cannot be wiped off (leukoplakia, erythroplakia — rule out cancer)
• 3Multiple oral ulcers recurring monthly in a pattern
• 4Oral ulcers with genital ulcers and eye inflammation (Behçet's disease)
• 5Oral sores in an immunocompromised patient — may indicate oral candidiasis or viral reactivation

What you can do

• ✓Rinse with warm salt water or baking soda solution 3–4 times daily to promote healing
• ✓Avoid spicy, acidic, or abrasive foods that aggravate sores
• ✓Switch to a toothpaste without sodium lauryl sulfate — shown to reduce aphthous ulcer frequency
• ✓OTC gels containing benzocaine provide temporary pain relief
• ✓Ensure adequate intake of iron, B12, and folate — deficiencies contribute to recurrent ulcers

Conditions that cause this symptom

Medications that may help

Treatment depends on the underlying cause. Always consult your provider before starting any medication.

Frequently asked questions