Mouth Ulcers: Causes & Best Remedies To Get Rid Of Them (Images Included)

Mouth ulcers, which are also called canker sores or tongue herpes, are typically small and painful lesions that develop in the mouth near the base of gums. They make it uncomfortable to talk, eat, and drink. Those at a higher risk of developing mouth ulcers include women, adolescents, and those with a family history of developing them.

Mouth ulcers typically clear up by themselves within a few weeks and aren’t contagious. If you get a large or particularly painful canker sore however, or if it persists for longer than a few weeks, then consult your doctor and seek their advice.

What Do Mouth Ulcers Look Like?

woman with ulcer painMouth ulcers typically present as round or oval sores developing on the cheeks, lips, and tongue. They are usually white, grey, yellow, or red in colour and are swollen. You may develop more than one ulcer at a time and they could spread and grow.

A mouth ulcer is different from a cold sore, which is a small blister that develops on the lips and around the mouth. A cold sore will usually initially present with an itching, tingling, or burning sensation around the mouth.

The Symptoms Of Different Mouth Ulcer Types

There are three main varieties of canker sore; minor, major, and herpetiform.


Minor canker sores are small round or oval ulcers that will take a few weeks to heal and shouldn’t scar.


Major canker sores will be larger and deeper than the minor variety. They usually have irregular edge and take longer to heal – up to six weeks. A major mouth ulcer can cause long-term scarring.


Herpetiform canker sores will be pinpoint size and occur in clusters of between 10 and 100. They primarily affect adults. They also have irregular edges but should clear up in a matter of weeks without scarring.

What Causes Mouth Ulcers

More often than not it’s not clear what causes a mouth ulcer to develop. A single mouth ulcer is typically caused by the lining of the inside of the mouth being damaged such as:

  • Minor injuries caused by brushing, dental work, a sports injury, or an accidental bite
  • Hard food
  • Ill-fitting dentures
  • Defective fillings

It’s not always clear to determine what causes ulcers that keep coming back, but there are several potential triggers including:

  • Stress and anxietytoothbrush with toothpaste
  • Eating certain foods such as spicy foods, chocolate, coffee, almonds, peanuts, cheese, strawberries, tomatoes, and wheat flour
  • Hormonal changes – women sometimes develop mouth ulcers during menstruation
  • Toothpaste that contains sodium lauryl sulphate
  • Stopping smoking – you may develop mouth ulcers when you initially stop smoking

It’s believed that genes may play a part in developing mouth ulcers as around 40% of people who continue developing mouth ulcers say that the problem runs in their family.

Medical Conditions

It’s possible that a mouth ulcer may be caused by a medical condition, including:

  • Viral infections – chickenpox, the cold sore virus, and hand, foot, and mouth disease are known to cause ulcers
  • Vitamin B12 and iron deficiencies
  • Crohn’s disease – this is a long-term condition that causes the lining of the digestive system to be inflamed
  • Coeliac disease – this digestive condition causes adverse reactions to gluten
  • Reactive arthritis – this condition causes inflammation around the body, typically in response to infections
  • A weakened immune system – such as from lupus or HIV
  • Behcet’s Disease – this rare and poorly understood condition can cause swelling in the blood vessels.

Treatments And Medications

Mouth ulcers are sometimes caused by medications and treatments including:

  • Non-steroidal anti-inflammatory drugs (NSAIDS) – such as ibuprofen
  • Nicorandil – an angina medication
  • Beta-blockers – another angina medication, beta blockers are also used for abnormal heart rhythms and high blood pressure
  • Radiotherapy and chemotherapy – mouth ulcers are a side effect of these treatments, with the effect called mucositis.

Is It A Form Of Mouth Cancer?

working dentistThere are some cases where a long-lasting mouth ulcer is a sign of a mouth cancer. Ulcers that are caused by mouth cancer typically appear on or under the tongue, but they can develop elsewhere in the mouth.

The risk factors of mouth cancer include:

  • Smoking or other tobacco products
  • Drinking alcohol – smokers who also drink heavily are at a greater risk of developing mouth cancer than the general population
  • Infection with human papilloma virus (HPV) – the virus that causes genital warts

Mouth cancers and mouth ulcers have distinctive symptoms. There are some key differences between mouth ulcers and what could be mouth cancer:

  • Mouth ulcers tend to be painful while mouth cancer isn’t
  • Mouth ulcers take a few weeks to clear up, while mouth cancer won’t go away by itself and can spread
  • Mouth cancer patches can be hard, rough, and difficult to remove
  • Mouth cancer will generally be a mixture of red and white areas or a large white area that appears on the tongue, on the gums, on the cheeks, or in the back of the mouth.

It’s important that you detect mouth cancer as soon as possible. Early detection and treatment of mouth cancer increase the chances of completely removing the cancer. Having regular dental checkups is the best way to detect early warning signs of mouth cancer.

When To Visit A Doctor

Mouth ulcers may be painful and make it difficult to eat, drink, and brush your teeth. Ulcers can often be treated at home. There are some cases when it’s best to talk to your doctor or dentist, including:

  • If the mouth ulcer lasts over three weeks
  • If you continue to get ulcers
  • If mouth ulcers spread to the lips
  • If you get fever and diarrhea when a canker sore appears
  • If the mouth ulcer becomes redder and more painful. This could be a sign of bacterial infection, which should be treated using antibiotics.

Mouth ulcers may be a symptom of a viral infection that predominately infects young children known as hand, foot, and mouth disease.

Treating Mouth Ulcers

There’s generally no need to treat mouth ulcers as they go away within a few weeks. Treatment can help to reduce discomfort and swelling though. This could be good if your mouth ulcer makes it painful to eat and drink or if you keep getting them.


Here’s a look at what you can do to speed up the healing process:

  • Applying protective paste from a pharmacist
  • Brushing your teeth with a soft toothbrush
  • Using a toothpaste free from sedum lauryl sulphate which may be an irritant
  • Avoiding hard, salty, spicy, acidic and hot foods and rinks while ulcers heal
  • Drinking plenty of water
  • Drinking cool drinks with a straw
  • Avoiding things that may trigger the mouth ulcers
  • Rinsing with saltwater and baking soda
  • Putting milk of magnesia on the mouth ulcer and using baking soda paste to cover mouth ulcers
  • Placing a damp tea bag on the mouth ulcer
  • Trying a natural remedy such as myrrh, licorice, Echinacea and chamomile tea

Pharmaceutical Medications

There are several mouth ulcer treatments available from the pharmacy. Talk to your pharmacist about which treatment would be right for you. Here are some options:

  • Antimicrobial mouthwash might speed up the healing process and prevent the ulcer becoming infected. This treatment shouldn’t be used with children under two. It may also contain chlorhexidine gluconate, which can stain teeth. These stains fade when the treatment is over though.
  • Painkillers can be found in the form of mouthwash, gel, spray, and lozenges. It may sting when you first use one and they can numb your mouth, but these effects are temporary. Mouthwash could be diluted using water if the stinging persists. Children under 12 should avoid using mouthwash and gel, and mouthwash shouldn’t be used for over seven days straight.
  • Corticosteroid lozenges can speed up healing and reduce pain. It’s best to use these lozenges once ulcers develop, but they shouldn’t be given to children under 12.

Prescription Medication from Doctors And GPs

Your doctor may prescribe you with stronger corticosteroids to reduce the pain and swelling and further enhance healing. Prescription corticosteroids are available as tablets, pastes, mouthwash, and sprays, but they aren’t suitable for children under 12.

Tips For Preventing Mouth UlcersPhoto of young couple having fun while brushing teeth in the bathroom.

It might not be possible to prevent a mouth ulcer because they are often caused by things outside of your control such as medical conditions and family history. There are some things you can do to help reduce your risk of developing a mouth ulcer however, including:

  • Avoiding foods that irritate the mouth; this includes acidic fruits like pineapple, oranges, grapefruit, and lemon. Avoiding nuts, chips, and spicy food can help too. Eat whole grains and alkaline (nonacidic) fruits and vegetables instead. Eat a healthy and well-balanced diet and take daily multivitamins.
  • Don’t chew gum and avoid talking while chewing to avoid accidentally biting yourself
  • Brushing your teeth using a soft-bristled brush as this irritates the mouth less
  • Using toothpaste free from sodium lauryl sulphate
  • Reducing stress and anxiety, which can trigger mouth ulcers in some people
  • Lastly make sure you get plenty of rest and sleep; this comes with a whole host of benefits including preventing mouth ulcers and other health problems