Mouth ulcers are very common. Most are harmless, painful for a few days, and heal by themselves within a week or two. They may appear on the inside of the cheeks, lips, tongue, floor of the mouth or soft palate. They can make eating, drinking, brushing and speaking uncomfortable.
But not every sore patch in the mouth should be ignored. An ulcer that lasts more than three weeks, keeps coming back, bleeds, grows, feels hard, appears with a lump, or comes with red or white patches needs checking by a dentist or GP. In a small number of cases, a persistent mouth ulcer can be an early sign of mouth cancer.
This guide explains common causes of mouth ulcers, what you can do at home, when a pharmacist can help, when to see a dentist or GP, and the red flags that should never be ignored.
You may also find these related guides useful: Bad Breath: Dental Causes and Treatment, Dental Abscess: Symptoms and Treatment, Swollen Face from a Tooth: When It Is an Emergency, Broken Tooth: What to Do, Lost Filling or Crown: What to Do and How to Choose a Dentist in the UK.
Quick summary
- Most simple mouth ulcers heal by themselves within 1 to 2 weeks.
- See a GP or dentist if a mouth ulcer lasts longer than 3 weeks.
- Red flags include a non-healing ulcer, red or white patches, a lump in the mouth or neck, unexplained bleeding, numbness, persistent pain, difficulty swallowing or speaking, and unexplained weight loss.
- Common causes include biting the cheek, sharp teeth, braces, stress, hormonal changes, certain foods, toothpaste irritation, infections, medicines, vitamin deficiencies and inflammatory conditions.
- Mouth ulcers are not the same as cold sores. Cold sores usually appear on or around the lips and are caused by a virus.
- A pharmacist can suggest protective gels, sprays, mouthwashes or pain relief for short-term ulcers.
- A dentist can check for sharp teeth, broken fillings, dentures, braces, gum problems, infection or suspicious patches.
- Do not ignore an ulcer because it is not painful. Some serious mouth changes can be painless at first.
- Children with mouth ulcers plus fever, rash, dehydration, severe pain or difficulty swallowing may need urgent advice.
- If you smoke, drink heavily, use smokeless tobacco, or have a previous history of mouth cancer, take persistent mouth changes seriously.
What is a mouth ulcer?
A mouth ulcer is a sore area where the surface lining of the mouth has broken down. It may look like a round or oval sore with a white, yellow or grey centre and a red border. Ulcers can be small and shallow, or larger and deeper.
Simple mouth ulcers are usually painful, especially when eating acidic, salty or spicy foods. They are different from mouth blisters, cold sores, oral thrush, gum abscesses and suspicious red or white patches.
The NHS says mouth ulcers are common and usually clear up on their own within a week or two, but you should see a GP or dentist if a mouth ulcer lasts longer than three weeks. NHS guidance on mouth ulcers is available here.
What do mouth ulcers look like?
A typical minor mouth ulcer may be:
- Round or oval.
- White, yellow or grey in the middle.
- Red around the edge.
- Painful or sore.
- Located on the inside of the lips, cheeks, tongue, floor of the mouth or soft palate.
- Small, often only a few millimetres across.
- Healed within 1 to 2 weeks.
More concerning mouth changes may look different. A persistent red patch, white patch, mixed red-and-white patch, hard ulcer, bleeding sore, lump, swelling or ulcer with numbness should be checked.
Common causes of mouth ulcers
Many mouth ulcers are caused by minor irritation or a temporary trigger. Sometimes no clear cause is found.
Accidental biting or trauma
Biting the inside of the cheek, lip or tongue can cause a painful ulcer. Trauma can also happen from sharp crisps, hard foods, toothbrush injury, dental treatment, sports injury or rubbing from dental appliances.
Sharp teeth, broken fillings or crowns
A sharp tooth edge, broken filling, rough crown or chipped tooth can repeatedly rub the same area and cause an ulcer. If the ulcer keeps returning in exactly the same place, a dentist should check for a local cause.
Related guides: Broken Tooth: What to Do and Lost Filling or Crown: What to Do.
Braces, retainers and dentures
Braces, wires, retainers, mouthguards and dentures can rub the mouth. A new denture or brace can cause temporary sore spots, but repeated ulcers should be adjusted by a dentist or orthodontist.
If your child has braces, read: Braces for Children: NHS and Private Options.
Stress, tiredness and illness
Some people notice mouth ulcers during stressful periods, poor sleep, exams, busy work periods or after viral illnesses. Stress does not mean the ulcer is “imaginary”; it may affect immune response, habits, eating patterns and mouth irritation.
Hormonal changes
Some people get mouth ulcers around their period, during pregnancy, during menopause or at times of hormonal change. If ulcers are frequent, severe or new, it is still worth discussing them with a dentist or GP.
Foods and drinks
Acidic, spicy or sharp foods can trigger or worsen ulcers in some people. Common irritants include citrus fruits, tomatoes, vinegar, spicy foods, crisps, nuts, alcohol and very hot drinks.
Toothpaste irritation
Some people with recurrent ulcers find that toothpaste containing sodium lauryl sulphate, often shortened to SLS, irritates their mouth. Switching to an SLS-free toothpaste may help some people, although it does not fix every case.
Vitamin or mineral deficiencies
Recurrent mouth ulcers can sometimes be linked with low iron, vitamin B12 or folate. If ulcers are frequent, severe or accompanied by tiredness, pale skin, pins and needles, dietary restriction or digestive symptoms, a GP may consider blood tests.
You may find these related guides useful: B12 and Folate Blood Test Results Explained and Iron, Ferritin and Anaemia Blood Test Results Explained.
Medicines
Some medicines can contribute to mouth ulcers, dry mouth, gum changes or mouth soreness. Do not stop prescribed medication without medical advice. If ulcers started after a new medicine, speak to a pharmacist, GP or dentist.
Medical conditions
Recurrent or severe mouth ulcers can sometimes be linked with conditions such as coeliac disease, inflammatory bowel disease, Behçet’s disease, immune problems, skin conditions affecting the mouth, or blood disorders.
Most mouth ulcers are not caused by serious disease, but recurring ulcers with other symptoms deserve proper assessment.
Mouth ulcer or cold sore?
Mouth ulcers and cold sores are often confused, but they are different.
| Feature | Mouth ulcer | Cold sore |
|---|---|---|
| Usual location | Inside the mouth | On or around the lips, sometimes around the mouth |
| Cause | Often trauma, irritation, aphthous ulcers or other triggers | Usually herpes simplex virus |
| Appearance | Round sore with white/yellow centre and red border | Small blisters that crust over |
| Contagious? | Simple mouth ulcers are not contagious | Cold sores are contagious |
| Treatment | Protective gels, mouthwashes, pain relief, treating triggers | Antiviral cream or tablets in selected cases |
If you are unsure whether you have an ulcer, cold sore, infection or another mouth problem, ask a pharmacist, dentist or GP.
Mouth ulcer or dental abscess?
A mouth ulcer is a sore on the lining of the mouth. A dental abscess is a collection of pus caused by infection, usually from a tooth or gum.
A dental abscess may cause:
- Throbbing toothache.
- Swelling of the gum, cheek, jaw or face.
- A gum boil or pimple-like swelling.
- Pus or a bad taste.
- Pain when biting.
- Fever or feeling unwell.
If you have swelling, pus, severe pain or fever, do not treat it as a simple mouth ulcer. Read: Dental Abscess: Symptoms and Treatment.
Red flags: when a mouth ulcer needs checking
Most mouth ulcers are not serious, but some features should prompt dental or medical assessment.
See a dentist or GP if:
- A mouth ulcer lasts longer than 3 weeks.
- An ulcer keeps coming back.
- An ulcer is getting bigger.
- An ulcer is unusually large or very painful.
- You have a lump in the mouth, lip, jaw, neck or throat.
- You have a red, white or red-and-white patch in the mouth.
- You have bleeding from the ulcer without an obvious cause.
- You have numbness in the tongue, lip, chin or mouth.
- You have pain in the mouth that does not go away.
- You have difficulty swallowing, chewing, speaking or moving the tongue or jaw.
- Your voice is hoarse and does not settle.
- A denture suddenly stops fitting properly.
- You have unexplained loose teeth.
- You are losing weight without trying.
- You feel generally unwell or have repeated infections.
NHS mouth cancer guidance says to see a GP if you have a mouth ulcer lasting more than 3 weeks, a lump in the mouth, lip, neck or throat, a red or white patch, persistent mouth pain, difficulty swallowing or speaking, or a hoarse voice that does not go away. NHS mouth cancer symptom guidance is available here.
Why the 3-week rule matters
A simple trauma ulcer, such as one caused by biting the cheek, should usually improve and heal. If an ulcer is still present after 3 weeks, it needs checking because it may not be a simple ulcer.
A persistent ulcer does not automatically mean cancer. It may be caused by ongoing trauma, denture rubbing, immune conditions, infection or other causes. But the important point is that it should be examined rather than watched indefinitely.
Mouth cancer red flags
Mouth cancer can affect the tongue, gums, floor of the mouth, inside of the cheeks, lips, palate, tonsil area and throat. It is more common in people who smoke, drink heavily, use smokeless tobacco or have certain viral risk factors, but it can occur in people without obvious risk factors too.
Possible warning signs include:
- An ulcer that does not heal within 3 weeks.
- A red patch.
- A white patch.
- A mixed red-and-white patch.
- A lump or thickened area in the mouth.
- A lump in the neck.
- Pain or soreness that does not go away.
- Numbness or altered feeling.
- Difficulty swallowing.
- Difficulty moving the tongue or jaw.
- Hoarseness that persists.
- Unexplained loose teeth.
- Unexplained weight loss.
Do not wait for pain. Some early mouth cancers are not very painful at first.
Who is at higher risk of mouth cancer?
Mouth cancer risk is higher in some groups, although anyone can develop suspicious mouth changes.
Risk factors include:
- Smoking cigarettes, cigars or pipes.
- Using smokeless tobacco, chewing tobacco, paan or betel quid.
- Heavy alcohol use.
- Smoking and heavy alcohol together, which increases risk further.
- Previous mouth cancer or head and neck cancer.
- Human papillomavirus, especially for some throat cancers.
- Long-term immune suppression.
- Older age, although younger people can still be affected.
If you are in a higher-risk group and notice a persistent ulcer or patch, book an assessment promptly.
What can you do at home for a simple mouth ulcer?
If the ulcer is small, typical, clearly linked to minor trauma, and improving, self-care may be enough.
Helpful steps include:
- Avoid spicy, salty, acidic or sharp foods until it heals.
- Use a soft toothbrush.
- Drink cool fluids if the mouth feels sore.
- Avoid alcohol and smoking, which can irritate the mouth.
- Use a straw if drinks sting, but avoid very hot drinks.
- Try an SLS-free toothpaste if ulcers are recurrent and toothpaste seems to trigger them.
- Keep the mouth clean with gentle brushing.
- Use pain relief if suitable for you.
Do not put aspirin directly on an ulcer. It can burn the mouth lining.
Can a pharmacist help with mouth ulcers?
Yes. A pharmacist can suggest treatments to reduce pain, protect the ulcer and help you eat and brush more comfortably while it heals.
Options may include:
- Protective ulcer gels or pastes.
- Antiseptic mouthwash.
- Pain-relieving mouthwash or spray.
- Medicated lozenges.
- Advice on suitable painkillers.
- Advice on whether you need a dentist or GP.
NHS Inform says a pharmacist may advise seeing a GP or dentist if an ulcer has lasted 3 weeks, keeps coming back, grows larger than usual, is near the back of the throat, or becomes more painful or red. NHS Inform mouth ulcer guidance is available here.
When should you see a dentist?
A dentist is often the best professional to check mouth ulcers because they can examine the teeth, gums, tongue, cheeks, lips, palate, dentures and dental work.
See a dentist if:
- An ulcer may be caused by a sharp tooth, broken filling, crown, denture or brace.
- An ulcer is on the gum near a painful tooth.
- You have toothache, swelling, pus or bad taste.
- You have a sore under a denture.
- You have red or white patches in the mouth.
- You have a lump, swelling or non-healing sore.
- You have ulcers plus bleeding gums or gum disease signs.
- You are worried about mouth cancer.
Dentists are trained to examine the mouth for suspicious changes. If needed, they can refer you urgently to an oral medicine, oral surgery or hospital specialist service.
When should you see a GP?
A GP may be the right route if ulcers are recurrent, widespread, linked with general symptoms, or possibly caused by a medical condition.
See a GP if you have mouth ulcers with:
- Fever or feeling very unwell.
- Weight loss.
- Diarrhoea, abdominal pain or blood in stool.
- Joint pains.
- Genital ulcers.
- Eye inflammation.
- Skin rashes.
- Severe tiredness.
- Repeated infections.
- Possible medicine side effects.
- Signs of anaemia or vitamin deficiency.
If you have a dental cause such as a sharp tooth, dental abscess, broken tooth or denture sore, a dentist is usually needed as well.
Mouth ulcers in children
Children can get mouth ulcers from cheek biting, viral infections, minor injuries, braces, hot foods, toothbrush trauma or hand, foot and mouth disease. Most simple ulcers settle, but children can become dehydrated if their mouth is too painful to drink.
Seek advice if a child has:
- Mouth ulcers with fever.
- Rash on hands, feet or body.
- Difficulty drinking.
- Signs of dehydration, such as fewer wet nappies or very dark urine.
- Severe pain.
- Ulcers lasting more than 3 weeks.
- Repeated ulcers.
- Swelling of the face, jaw or gums.
- Toothache or dental trauma.
For wider dental prevention advice, read: Children’s Teeth: Complete UK Parent Guide.
Mouth ulcers from braces or dentures
Braces and dentures can rub the soft tissues and cause ulcers. This is especially common when a new appliance is fitted or adjusted.
You can try:
- Orthodontic wax for braces that rub.
- Returning to the dentist or orthodontist for adjustment.
- Removing dentures at night if advised.
- Cleaning dentures carefully every day.
- Not wearing a painful denture until it has been checked, if it is causing damage.
A denture sore that does not heal after adjustment, or a sore under a denture lasting more than 3 weeks, should be checked.
Related guide: Dentures in the UK.
Recurrent mouth ulcers
Some people get mouth ulcers repeatedly. These may be aphthous ulcers, sometimes called recurrent aphthous stomatitis. They are not contagious and often have no single clear cause.
NICE describes aphthous ulcers as painful, clearly defined, round or oval shallow ulcers confined to the mouth and not associated with systemic disease. NICE CKS information on aphthous ulcers is available here.
If ulcers are recurrent, keep a diary of:
- When they appear.
- How long they last.
- Where they occur.
- Foods or drinks before they appear.
- Stress, illness or hormonal timing.
- Toothpaste changes.
- Medicines.
- Other symptoms.
Recurrent ulcers may need assessment for triggers, deficiencies, inflammatory disease or medication effects.
Large or severe mouth ulcers
Larger ulcers can be more painful and may take longer to heal. Some can leave scarring. Severe ulcers may affect eating, drinking, sleep and speech.
See a dentist or GP if:
- The ulcer is unusually large.
- You have several ulcers at once.
- You cannot eat or drink properly.
- Pain relief is not helping.
- Ulcers keep returning.
- The ulcer is near the back of the throat.
- The ulcer lasts longer than 3 weeks.
Can mouth ulcers be caused by infection?
Yes. Viral infections can cause mouth ulcers, especially in children. Hand, foot and mouth disease, herpes infections and other viral illnesses can cause painful sores.
Bacterial infection is less common as a simple cause of mouth ulcers, but an ulcer can become more painful, red or inflamed. Dental infections can also cause gum boils, pus and swelling that may be mistaken for ulcers.
Seek advice if ulcers come with fever, spreading redness, pus, facial swelling or a child who cannot drink.
Can mouth ulcers be linked with gut problems?
Recurrent mouth ulcers can sometimes occur with digestive conditions such as coeliac disease, Crohn’s disease or ulcerative colitis.
Speak to a GP if ulcers occur with:
- Ongoing diarrhoea.
- Blood in stool.
- Unexplained weight loss.
- Abdominal pain.
- Poor growth in children.
- Severe tiredness or anaemia.
Related guides: Coeliac Disease: Symptoms, Testing and Treatment and Inflammatory Bowel Disease Explained.
Can mouth ulcers be linked with vitamin deficiency?
Sometimes. Low iron, vitamin B12 or folate may contribute to recurrent mouth ulcers, mouth soreness, tongue changes or tiredness.
A GP may consider blood tests if ulcers are frequent or accompanied by symptoms such as:
- Fatigue.
- Pale skin.
- Dizziness.
- Shortness of breath on exertion.
- Changed tongue appearance.
- Pins and needles.
- Restricted diet.
- Heavy periods.
- Digestive symptoms.
How are mouth ulcers treated?
Treatment depends on the cause, severity and whether there are red flags.
Simple short-term ulcers
These often need only self-care and pharmacy treatments for comfort. Protective gels, antiseptic mouthwashes and pain-relieving sprays may help.
Trauma ulcers
If an ulcer is caused by a sharp tooth, denture, filling or brace, the source of rubbing needs adjusting. Otherwise the ulcer may keep returning.
Recurrent aphthous ulcers
Treatment may include trigger management, topical steroid preparations prescribed by a clinician, mouthwashes, deficiency checks or assessment for underlying conditions if symptoms suggest them.
Infection-related ulcers
Viral ulcers usually need supportive care, but some infections may need specific treatment. Dental infections need dental treatment, not just ulcer gel.
Suspicious ulcers or patches
A persistent ulcer, suspicious patch or lump may need urgent referral. The specialist may examine the area and sometimes take a biopsy to find out what it is.
Can antibiotics treat mouth ulcers?
Most simple mouth ulcers do not need antibiotics. Antibiotics are only useful if there is a bacterial infection or specific dental infection that requires them.
Do not take leftover antibiotics for mouth ulcers. If there is swelling, pus, fever or dental infection, you need proper assessment.
Can mouthwash help mouth ulcers?
Mouthwash may help depending on the type. Some mouthwashes reduce bacteria, some numb pain, and some are prescribed for inflammation. However, strong alcohol-based mouthwashes can sting or irritate ulcers.
Ask a pharmacist, dentist or GP which mouthwash is suitable, especially for children, pregnancy, recurrent ulcers, dry mouth or medical conditions.
How to prevent mouth ulcers
Not all mouth ulcers can be prevented, but you may reduce risk by avoiding known triggers and protecting the mouth from trauma.
- Use a soft toothbrush.
- Brush gently but thoroughly.
- Have sharp teeth, broken fillings or rough crowns checked.
- Have dentures adjusted if they rub.
- Use orthodontic wax if braces rub.
- Avoid foods that repeatedly trigger ulcers.
- Try SLS-free toothpaste if toothpaste seems to irritate your mouth.
- Manage stress and sleep where possible.
- Do not smoke or use smokeless tobacco.
- Limit alcohol if it irritates the mouth.
- Attend regular dental check-ups.
What will a dentist or GP do?
A clinician may ask how long the ulcer has been there, whether it is painful, whether it has changed, whether you have had it before, and whether you have other symptoms.
They may check:
- The ulcer’s size, shape, colour and texture.
- Whether it feels firm or fixed.
- Whether there are red or white patches.
- Whether there are lumps in the mouth or neck.
- Whether teeth, fillings, dentures or braces are rubbing.
- Whether there are signs of dental infection.
- Medication history.
- Smoking and alcohol history.
- General symptoms such as weight loss, fever or digestive symptoms.
Depending on findings, they may offer treatment, arrange blood tests, adjust dental work, prescribe medication or refer you to a specialist.
When is urgent referral needed?
NICE guidance on head and neck cancer recognition includes urgent referral criteria for suspicious oral lesions, including unexplained ulceration in the oral cavity lasting more than 3 weeks and persistent unexplained lumps in the neck. NICE CKS head and neck cancer recognition guidance is available here.
An urgent referral does not mean you definitely have cancer. It means the change needs specialist assessment quickly.
Questions to ask your dentist or GP
- Does this look like a simple mouth ulcer?
- Could a tooth, filling, denture or brace be causing it?
- How long should it take to heal?
- What should I use for pain relief?
- Should I change toothpaste or mouthwash?
- Do I need blood tests for iron, B12 or folate?
- Could my medication be contributing?
- Do I need referral to oral medicine or oral surgery?
- Does this need urgent cancer pathway referral?
- What should I do if it gets bigger or does not heal?
Red flags to watch out for
Do not ignore:
- An ulcer lasting longer than 3 weeks.
- An ulcer that is growing.
- A hard or painless ulcer.
- A red or white patch.
- A lump in the mouth, lip, jaw, neck or throat.
- Bleeding without an obvious cause.
- Numbness or tingling in the mouth, tongue, lip or chin.
- Difficulty swallowing, speaking or moving the tongue.
- Persistent hoarseness.
- Unexplained loose teeth.
- A denture that suddenly stops fitting.
- Unexplained weight loss.
- Facial swelling, fever or severe dental pain.
How to choose who to see
If the ulcer seems related to teeth, braces, dentures, fillings, crowns, gum swelling or toothache, start with a dentist.
If ulcers are recurrent, widespread, linked with general symptoms, or you cannot access a dentist, speak to a GP. A pharmacist can help with short-term symptom relief and advise whether you need further assessment.
You can browse local dental providers through All Health and Care, including our Top 10 Dentists in the UK and local pages such as Top 10 Dentists in London.
Final thoughts
Most mouth ulcers are painful but harmless and heal within a week or two. They are often caused by minor trauma, stress, foods, braces, dentures or temporary irritation.
The important safety message is simple: a mouth ulcer that lasts longer than 3 weeks should be checked by a dentist or GP. The same applies to red or white patches, lumps, unexplained bleeding, numbness, persistent pain, difficulty swallowing or speaking, and unexplained weight loss.
Getting checked does not mean assuming the worst. It means not missing something important. Early assessment is especially important for mouth cancer, dental infection and ulcers linked with wider health conditions.
For more patient-friendly dental guides, visit our Dental Health & Dentistry section.
Frequently asked questions about mouth ulcers
How long do mouth ulcers usually last?
Most simple mouth ulcers heal within 1 to 2 weeks. An ulcer lasting longer than 3 weeks should be checked by a dentist or GP.
When should I worry about a mouth ulcer?
Worry if it lasts more than 3 weeks, grows, bleeds, feels hard, keeps returning, appears with a lump, or comes with red or white patches, numbness, persistent pain or difficulty swallowing.
Can a mouth ulcer be cancer?
Most mouth ulcers are not cancer. However, a non-healing ulcer can be a symptom of mouth cancer, so ulcers lasting more than 3 weeks need checking.
Are mouth ulcers contagious?
Simple aphthous mouth ulcers are not contagious. Cold sores are contagious and usually appear on or around the lips.
What causes mouth ulcers?
Causes include cheek biting, sharp teeth, braces, dentures, stress, certain foods, toothpaste irritation, infections, medicines, vitamin deficiencies and some medical conditions.
Can stress cause mouth ulcers?
Stress may trigger or worsen ulcers in some people, although it is not the only cause.
Can toothpaste cause mouth ulcers?
Some people find toothpaste containing sodium lauryl sulphate irritates the mouth. Switching to SLS-free toothpaste may help recurrent ulcers in some cases.
Can braces cause mouth ulcers?
Yes. Brackets and wires can rub the mouth. Orthodontic wax and adjustment by the orthodontist can help.
Can dentures cause mouth ulcers?
Yes. Poorly fitting or new dentures can rub and cause sore spots. A dentist should adjust dentures that cause repeated ulcers.
Can a broken tooth cause a mouth ulcer?
Yes. A sharp broken tooth or filling can rub the cheek or tongue and cause a trauma ulcer.
What can I put on a mouth ulcer?
A pharmacist can suggest protective gels, pastes, sprays or mouthwashes. Avoid putting aspirin directly on the ulcer.
Do antibiotics help mouth ulcers?
Most mouth ulcers do not need antibiotics. Antibiotics may be needed only if there is bacterial infection or dental infection, and this should be assessed properly.
Can mouthwash help mouth ulcers?
Some mouthwashes can reduce pain or bacterial build-up, but alcohol-based mouthwashes may sting. Ask a pharmacist, dentist or GP what is suitable.
Why do I keep getting mouth ulcers?
Recurrent ulcers may be linked with stress, trauma, foods, toothpaste irritation, deficiencies, medicines or medical conditions. See a dentist or GP if they keep returning.
Can low iron cause mouth ulcers?
Low iron can contribute to mouth soreness or recurrent ulcers in some people. A GP may consider blood tests if symptoms suggest deficiency.
Can B12 deficiency cause mouth ulcers?
Vitamin B12 deficiency can be linked with mouth soreness, tongue changes and ulcers. Blood tests may be needed if symptoms fit.
Can children get mouth ulcers?
Yes. Children can get ulcers from minor trauma, viral infections, braces, hot foods or other causes. Seek advice if they cannot drink, have fever, rash, severe pain or ulcers lasting more than 3 weeks.
Are mouth ulcers common after dental treatment?
They can happen after accidental rubbing, injections, impressions, sharp temporary restorations or dental appliances. If an ulcer does not heal, contact the dentist.
Should I see a dentist or GP for a mouth ulcer?
See a dentist if it may be linked to teeth, dentures, braces, gum problems or dental infection. See a GP if ulcers are recurrent, widespread or linked with general symptoms. Either can assess red flags.
Can mouth ulcers cause bad breath?
A simple ulcer may cause local soreness, but persistent bad breath is more often linked with plaque, gum disease, tongue coating, dry mouth, decay or infection.
Can mouth ulcers appear on the tongue?
Yes. Ulcers can appear on the tongue. A tongue ulcer lasting more than 3 weeks, or associated with a lump, numbness or persistent pain, should be checked.
Can mouth ulcers appear on the gum?
Yes, but a sore or swelling on the gum may also be a gum boil or dental abscess. If there is pus, toothache or swelling, see a dentist urgently.
Can spicy foods make mouth ulcers worse?
Yes. Spicy, salty and acidic foods often sting and may make symptoms worse while the ulcer heals.
Can mouth ulcers be linked with Crohn’s or coeliac disease?
Recurrent mouth ulcers can sometimes occur with digestive conditions. See a GP if ulcers come with diarrhoea, abdominal pain, weight loss, blood in stool or anaemia symptoms.
Can smoking affect mouth ulcers?
Smoking can irritate the mouth and increases mouth cancer risk. A persistent ulcer in someone who smokes should be checked promptly.
What is the most important mouth ulcer red flag?
The most important red flag is an ulcer that does not heal within 3 weeks. It should be checked by a dentist or GP.
