Mouth ulcers

Mouth ulcers are small painful sores that develop in the mouth, often inside the cheeks or at the bottom of the gums. The most common type are aphthous ulcers, which are small swollen greyish/white or red sores, where the top layer of the skin is damaged.

At least one in five people suffer from recurrent bouts of mouth ulcers. They are sometimes a sign of being run down, and some are associated with deficiencies in iron, folic acid or vitamin B12. They can also be caused by lack of vitamin C.


Single ulcers can be caused by damage from biting the inside of your cheek or sharp teeth, over-zealous tooth brushing, or poorly fitting dentures or braces. Around 40 per cent of people suffering from recurrent ulcers report it runs in their family.

Sometimes mouth ulcers are triggered by anxiety or stress or changes in hormone levels, with some women only developing them during their periods. Stopping smoking can be another cause although this is usually temporary. Eating certain foods, including chocolate, spicy foods, coffee, cheese, tomatoes, peanuts and almonds; and using toothpaste containing sodium lauryl sulphate may also be triggers.

Deficiencies in vitamin B12 and iron can lead to mouth ulcers, because the cells of the lining of the mouth need these nutrients to regenerate efficiently. A study, published in The Journal of Oral Pathology and Medicine found that of 330 patients with ulcers, 39 were deficient in either iron, folic acid, vitamin B12 or a combination of all these nutrients. When given supplements, 23 showed a complete remission of ulcers, 11 improved and five were not helped.

Other underlying medical conditions include viral infections, such as cold sores or hand, foot and mouth disease and gastrointestinal diseases, such as coeliac disease, an autoimmune condition where your body produces antibodies to gluten.

Mouth cancer may be suspected where an ulcer lasts a long time without any obvious cause. If a mouth ulcer persists longer than three weeks, it should be checked by your dentist or GP.

Non-steroidal anti-inflammatory drugs(NSAIDs) including ibuprofen; beta-blockers such as propranolol, which are used to treat angina and high blood pressure; and nicorandil, used for angina, may cause a reaction that leads to mouth ulcers. However, very often there isn't any apparent cause for mouth ulcers.


Mouth ulcers usually form on the inside of the lips and cheeks, on the floor of the mouth and under the tongue.

Eighty per cent of ulcers are classed as minor, measuring two to 8mm in diameter, and usually heal within two weeks. Major ulcers are larger (1cm or more) and have a raised irregular border and can heal over several weeks, often scarring. Herpetiform ulcers are pin-head sized ulcers that may fuse together to make larger, irregular-shaped ulcers which are extremely painful.


Mouth ulcers don’t generally need a diagnosis from a doctor, but, as stated, if you have had one that’s lasted more than three weeks, you should see your dentist or GP to check it's not mouth cancer. If they suspect an underlying cause, they may do blood tests to measure the inflammation in your body, as well as checking your iron and vitamin B12 levels.

Who gets mouth ulcers?

Mouth ulcers are more common in women than in men, teenagers and young adults.


Fortunately, most mouth ulcers don’t need to be treated and usually heal by themselves within a week or two.

Antimicrobial mouthwashes, such as chlorhexidine gluconate, may speed up the healing and prevent infection, particularly if it’s too painful to brush the teeth.If the ulcer is painful, try using painkiller mouthwashes, spray, lozenges or gel directly.

You may also be able to use corticosteroid lozenges, which reduce pain and speed up healing, and your GP may also prescribe a corticosteroid mouthwash, paste or spray.

Self-help measures include using a softer toothbrush and switching to toothpaste free of sodium lauryl sulphate. Avoid foods that are spicy, salty, acidic or hot food and drink, and reduce your stress levels by learning relaxation techniques, such as yoga, meditation, and through exercise.

A multivitamin and mineral supplement, containing iron, B12 and vitamin C may help correct any nutritional deficiencies.

Nothing beats a healthy, balanced diet to provide all the nutrients we need. But when this isn't possible, supplements can help. This article isn't intended to replace medical advice. Please consult your healthcare professional before trying supplements or herbal medicines.

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