Oral Health Library · 10 min read

Why Do I Keep Getting Mouth Ulcers?

Mouth ulcers often keep coming back because of a tendency to develop common recurring sores, repeated injury, stress, or poor sleep. Sometimes, low nutrient levels or another health condition contribute. Frequent episodes need assessment, and any single ulcer lasting beyond two weeks needs an in-person examination, even if it is painless.

Written and medically reviewed by

Dr. Bipin R. Upadhyay

BDS · MDS Oral Medicine & Radiology · PhD Scholar · Associate Professor & Head, Department of Dentistry

Last clinically reviewed: 2026-10-30

Key points

  • Recurring mouth ulcers often have several possible triggers, not one clear cause.
  • A sore that heals and returns is different from one that never heals.
  • Frequent or disruptive episodes need assessment; any single ulcer lasting beyond two weeks needs an in-person examination.
  • A lump, numbness, unexplained bleeding, or difficulty opening the mouth or swallowing needs prompt attention.
  • Care focuses on comfort, removing irritation, and treating any confirmed underlying cause.

What are recurring mouth ulcers?

A mouth ulcer is a break in the soft lining inside the mouth. It may look like a small round or oval sore with a pale centre and a red edge. Eating, drinking, or brushing can make it sting.

A common type is called an aphthous ulcer, sometimes called a canker sore. These sores often appear inside the lips or cheeks, under the tongue, or on other soft areas. They are not contagious and cannot be passed through sharing meals.

Many small, common ulcers heal within one to two weeks without leaving a scar. Some people have only occasional episodes, while others develop new sores regularly. Larger, deeper, or unusually painful sores need assessment rather than an assumption that they are ordinary ulcers.

  • Recurring ulcers heal, then another sore appears later.
  • A persistent ulcer stays in place without fully healing.
  • Repeated sores in exactly the same place may point to ongoing rubbing or another local problem.
  • Appearance alone cannot confirm the cause, especially from a photograph.

Why do mouth ulcers keep coming back?

There is not always one clear cause. In common recurring ulcers, the body's defence system appears to react in the mouth lining. A family tendency can also play a part, but this does not automatically mean the person has weak immunity.

Triggers differ from person to person. Stress and poor sleep may be linked with episodes, but they should not be used to explain every sore without an examination. A trigger diary can help reveal patterns without blaming a single food or habit.

Some people notice ulcers around hormonal changes or during periods of illness. Others cannot identify any trigger. Ulcers that suddenly become frequent, especially in someone who rarely had them before, deserve a review.

  • Minor injury from cheek biting or brushing.
  • Rubbing from a sharp tooth, dental appliance, or denture.
  • Stress, disturbed sleep, or a recent illness.
  • Low levels of certain nutrients.
  • Less commonly, a wider health condition or a reaction to an existing treatment.

Could a tooth, food, or daily habit be irritating my mouth?

A sharp tooth edge, rough filling, or poorly fitting denture can repeatedly damage the same area. A dental examination can identify the source. Pain settling briefly does not mean the rubbing has been corrected.

Spicy, sour, very hot, or rough foods can sting an existing ulcer. That does not prove that these foods caused it. There is no single food restriction that prevents mouth ulcers for everyone, so avoid cutting out many nutritious foods without guidance.

In India, recurrent sores are sometimes described as body heat or blamed entirely on digestion. These descriptions do not identify a medical cause. Persistent symptoms need an examination rather than repeated changes in home remedies.

  • Notice whether the sore touches a sharp tooth or appliance.
  • Choose a soft toothbrush and avoid forceful brushing.
  • Avoid picking, scraping, or biting the sore.
  • Do not try to file a tooth or adjust a denture at home.
  • Avoid tobacco, gutkha, and areca nut, including supari.

Can repeated ulcers signal another health problem?

Sometimes, repeated ulcers are associated with low nutrient levels. This may happen because of limited food intake, blood loss, or difficulty absorbing nutrients from food. Ulcers alone cannot show whether a deficiency is present.

Less commonly, ulcers occur with diseases affecting the gut, the body's defence system, or the skin and other body surfaces. An examination and the pattern of symptoms help decide whether these possibilities need investigation. Most people with occasional small ulcers do not need extensive testing.

Existing prescribed or non-prescribed treatments may also be relevant. Bring a complete list to the appointment, but do not change prescribed treatment on your own.

  • Mention ongoing diarrhoea, abdominal pain, or unexplained weight loss.
  • Report unusual tiredness, paleness, fever, or frequent infections.
  • Tell the clinician about skin rashes, joint swelling, or sores in the genital area.
  • Eye pain, redness, or blurred vision alongside ulcers needs urgent medical assessment.
  • In children, poor growth or repeated difficulty eating needs medical review.

When do mouth ulcers need an in-person examination?

Arrange an in-person examination for any single ulcer that has not healed beyond two weeks. Do not restart the count just because the pain improves. A sore that remains in the same place needs checking even if it is small or painless.

Book an appointment sooner if episodes are frequent, unusually large, or interfere with eating, drinking, sleep, or work. Ulcers that appear almost continuously also need assessment, even when each individual sore eventually heals.

Many persistent sores have non-cancerous causes, but an examination is needed to distinguish them. Tobacco use increases concern, yet people who do not use tobacco also need persistent ulcers checked.

  • Seek prompt examination for a lump in the mouth or neck.
  • Report numbness, unexplained bleeding, or a persistent red or white patch.
  • Difficulty opening the mouth or swallowing needs prompt assessment.
  • Rapidly increasing swelling, difficulty breathing, or inability to swallow saliva needs emergency care.
  • Inability to drink enough, very little urine, dizziness, or marked weakness needs urgent medical attention.
  • Severe ulcers with fever, especially in someone with reduced immunity, need urgent review.

What happens at a mouth-ulcer appointment?

A dentist or oral medicine specialist will ask when the problem began, how often it returns, and whether sores fully heal between episodes. An oral medicine specialist assesses diseases of the mouth lining and mouth symptoms linked to general health.

The examination usually includes the whole mouth, teeth, dental appliances, and neck. The clinician looks for rubbing, other patches, swelling, and changes around the sore. Depending on the findings, care may involve a dentist, physician, or another specialist.

Blood tests may be suggested when the history raises concern about low nutrient levels or another illness. They are not automatically needed for every small ulcer. A biopsy, which means taking a small tissue sample for laboratory examination, may be advised for an unexplained persistent or suspicious sore; this does not itself mean cancer.

  • Bring dated photographs if sores disappear before the appointment.
  • Note how long each sore lasts and whether it returns to the same place.
  • Describe symptoms elsewhere in the body.
  • Bring details of existing treatment, health conditions, and any tobacco or areca-nut use.

What does care for recurring mouth ulcers usually involve?

Care depends on the cause and how much the ulcers affect daily life. The aim is to reduce discomfort, support eating and drinking, and address any underlying problem. There is no single approach that prevents every future episode.

If a tooth or appliance is rubbing, dental correction may allow the area to heal. If testing confirms low nutrient levels, the clinician may recommend dietary support and appropriate correction. A suspected wider illness may need assessment with a physician.

For common recurring ulcers, a clinician may offer prescribed care to reduce pain and inflammation, meaning soreness and swelling. The choice depends on the examination, medical history, and severity. Reusing someone else's treatment or repeatedly treating an unexplained sore can delay the right diagnosis.

  • Relief of discomfort and support for normal eating.
  • Removal of repeated injury where present.
  • Management of a confirmed underlying cause.
  • Review if the ulcer fails to heal or the pattern changes.

What can make eating and mouth care more comfortable?

Gentle care can reduce irritation while a sore heals. It does not replace an examination when symptoms persist or warning signs are present. The aim is comfort, not to burn, dry out, or scrape away the ulcer.

Choose foods you can tolerate and keep meals balanced. If pain repeatedly limits food or fluid intake, seek care rather than managing with a very restricted diet. Children and older adults may need help maintaining intake during a painful episode.

  • Choose soft foods such as cooled khichdi, soft rice, or dal if comfortable.
  • Allow hot food and drinks to cool.
  • Avoid foods that clearly sting the sore while it is present.
  • Drink water regularly and watch for difficulty staying hydrated.
  • Keep teeth clean with gentle brushing.
  • Avoid applying concentrated household substances or harsh home remedies.
  • Do not place tobacco or areca nut against the sore.
  • Allow time for sleep and use manageable ways to reduce stress.

How can I track episodes and plan a review?

Keep a simple record of the date, location, size, and healing of each sore. Note possible rubbing, disrupted sleep, illness, or food-related discomfort. A pattern over several episodes is more useful than assuming the most recent meal caused the ulcer.

Plan an in-person review if ulcers keep returning or affect daily life. A video consultation may help organise the history, but it cannot replace feeling a lump, checking a sharp edge, or examining a persistent sore closely.

For people in Mumbai, Thane, Ambarnath, or nearby areas, a local dentist or oral medicine service is a suitable starting point. Dr. Bipin R. Upadhyay practises at the Special Dental OPD, K.J. Somaiya Super Speciality Hospital, Sion, Mumbai, and Reasonable Smile Dental Clinic, Ambarnath.

  • Track each sore separately rather than recording only the overall episode.
  • Seek earlier review if the pattern becomes more severe or frequent.
  • Have any ulcer lasting beyond two weeks examined, even after years of otherwise familiar episodes.

Questions people ask

Is it normal to get mouth ulcers every month?

A recurring pattern can happen with common aphthous ulcers, but monthly episodes deserve assessment if they are painful, numerous, or affect eating. A change from your usual pattern also matters.

Does getting ulcers mean I have a vitamin deficiency?

Not necessarily. Low nutrient levels are one possible contributor, but many people with recurring ulcers have no deficiency. Your history and examination help decide whether blood tests are useful.

Can stress cause mouth ulcers?

Stress and poor sleep may trigger episodes in some people. They are not a complete explanation for every ulcer. A persistent sore, lump, bleeding, or numbness still needs an examination.

Are recurring mouth ulcers a sign of cancer?

Common aphthous ulcers are not precancerous. However, an unexplained sore that does not heal may have a different cause. Any single ulcer lasting beyond two weeks needs an in-person examination.

Can I pass mouth ulcers to my family?

Common aphthous ulcers are not contagious. Some infections can also cause mouth sores, so a new illness with fever, blisters, or several affected family members needs assessment rather than assuming all sores are aphthous ulcers.

Why does an ulcer keep appearing in the same spot?

Repeated rubbing from a tooth, filling, denture, or appliance may be responsible. A clinician should check the area, especially if it never fully heals between episodes.

Should I worry if a mouth ulcer does not hurt?

Lack of pain does not prove a sore is harmless. Painless ulcers that persist beyond two weeks need examination, as do sores with a lump, numbness, unexplained bleeding, or difficulty swallowing.

Should I see a dentist or a physician for repeated ulcers?

A dentist or oral medicine specialist is a suitable starting point. A physician may also be needed if ulcers occur with digestive symptoms, fever, weight loss, or other changes in general health.

This page is general information, not a diagnosis. A mouth problem needs to be looked at in person or on video before anyone can tell you what it is.