Oral Medicine & Pathology
Mouth ulcers & lesions
Common sore spots in the mouth, and when they need checking.
Common cause
Minor injury, stress
Healing
1–2 weeks
Relief
Salt water rinses
See us if
Lasts 2+ weeks
Overview
Mouth ulcers are small, painful sores that can appear on the lips, cheeks, tongue or gums. Most are harmless and heal on their own within a week or two.
They can be triggered by minor injury, stress, certain foods or illness. An ulcer that does not heal or keeps coming back should be checked by your dentist.
What to know
- Most ulcers heal on their own in one to two weeks
- Often caused by minor injury, stress or food
- Salt water rinses can ease discomfort
- See us if a sore lasts more than two weeks
- Frequent or unusual ulcers should be checked
Common questions
What causes mouth ulcers?
Often a small injury, stress, certain foods, or being run down.
How can I ease the pain?
Warm salt water rinses and avoiding spicy or acidic foods can help.
When should I worry?
If an ulcer lasts more than two weeks or keeps returning, see us.
Are they contagious?
Common mouth ulcers are not contagious. Cold sores on the lip can be.
Can ulcers be a sign of something else?
Sometimes. Persistent or unusual sores should always be assessed.
Related topics
Dr Rick Iskandar · Reviewed June 2026