Mouth Ulcers: Causes, Relief and When to Worry
Most mouth ulcers heal themselves in under two weeks. The ones that do not are the ones that matter — and that rule is worth knowing.
Medically reviewed by Dr. Ashay Jain, BDS
In short: Most mouth ulcers heal within seven to fourteen days with salt-water rinses and a pharmacy gel. The rule that matters: any ulcer still present after two weeks needs examination — persistent, often painless ulcers are how oral cancer most commonly first presents, and India has among the world's highest rates.
Mouth ulcers are extremely common and usually harmless. They are also the symptom where a simple time rule genuinely matters, so it is worth reading to the end.
Why they happen
- Minor trauma. Biting your cheek, a sharp tooth edge, a rubbing denture or brace, or an aggressive toothbrush.
- Stress and lack of sleep. A very common trigger for recurrent ulcers.
- Nutritional deficiency. Iron, vitamin B12 and folate deficiency are associated with recurrent ulcers, and are worth testing if they keep returning.
- Hormonal changes.
- Certain foods, particularly acidic and spicy ones, in susceptible people.
- Underlying conditions, including coeliac disease and inflammatory bowel disease, which can present with recurrent oral ulcers.
What helps
- Warm salt-water rinses
- Topical gels from a pharmacy, used as directed
- Avoiding spicy, acidic, salty and very hot food while it heals
- A softer toothbrush and gentler brushing around the area
- Keeping the mouth clean — an infected ulcer heals slower
What makes them worse
Repeatedly touching or biting the area, harsh alcohol-based mouthwashes on an open ulcer, and continuing with whatever caused it — a sharp filling edge or a rubbing denture will keep producing an ulcer in the same spot until it is adjusted. An ulcer that keeps returning in exactly the same place usually has a mechanical cause a dentist can fix in minutes.
The two-week rule
This is the part worth remembering.
Any mouth ulcer that has not healed within two weeks should be examined by a dentist or doctor. Most will turn out to be harmless. But a persistent, non-healing ulcer is also the way oral cancer most commonly first presents, and India has among the highest rates of oral cancer in the world — largely linked to tobacco and areca nut use.
Get checked sooner rather than later if the ulcer is painless but persistent, has hard or raised edges, bleeds easily, or comes with a lump in the neck, numbness, or difficulty swallowing. Early detection changes outcomes substantially, and an examination takes minutes.
Getting it looked at
Every dentist on EnamDoc is verified against their dental council registration before they can accept a booking. If you use tobacco in any form, see tobacco and oral health.
General information, not a diagnosis. Any ulcer lasting more than two weeks needs to be examined in person.
Frequently asked
Frequently asked questions
How long should a mouth ulcer take to heal?
Most heal within seven to fourteen days. Any ulcer still present after two weeks should be examined by a dentist or doctor, regardless of whether it hurts.
Why do I keep getting mouth ulcers?
Common causes are stress, poor sleep, and iron, B12 or folate deficiency — worth testing if they recur. An ulcer returning in exactly the same spot usually has a mechanical cause such as a sharp tooth or rubbing denture.
Are mouth ulcers contagious?
Common aphthous ulcers are not. Cold sores, which appear on the lip rather than inside the mouth, are caused by a virus and are contagious.
When is a mouth ulcer serious?
If it lasts beyond two weeks, is painless but persistent, has hard or raised edges, bleeds easily, or comes with a neck lump, numbness or difficulty swallowing. Get examined promptly.
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