Mouth ulcers are a common yet painful affliction. They usually present as round or oval sores that are found inside the mouth, developing on the lips, cheeks or tongue. Their appearance can vary; mouth ulcers can be red, white, yellow, or grey and are usually swollen. A sufferer can also experience multiple mouth ulcers at a time, which unfortunately may spread and grow. Although very uncomfortable, mouth ulcers are in most cases harmless. Without treatment, the majority of mouth ulcers will clear up within a fortnight.

There are various possible causes of mouth ulcers. To learn more about this, visit our guide to mouth ulcer causes.

Mouth ulcers will present as round or oval sores that commonly appear inside the mouth. They can develop on the lips, inner cheeks or tongue. These swollen sores will be either red, white, yellow or grey in colour. Mouth ulcers are normally 2 - 8mm in diameter and may have a raised or defined border.

It is possible to present with multiple mouth ulcers at any given time. These sores can be painful and, depending on location, can make eating, drinking, talking and brushing teeth extremely uncomfortable.

In most cases, mouth ulcers can be treated at home; there is no need for an official diagnosis. It is only recommended you visit your doctor should any of the following apply:

• Your mouth ulcers are recurrent and frequent.
• Your mouth ulcers have persisted for longer than three weeks.
• Your mouth ulcers have become inflamed and painful, which may suggest a bacterial infection that will require treatment with antibiotics.
• You also have a fever, swollen glands or other signs of illness.

Mouth ulcers can also be a symptom of hand, foot and mouth disease, which is a viral infection that mainly affects young children. If you are worried or unsure about your mouth ulcers, it is advised to speak to a pharmacist, GP or dentist for an informed diagnosis.

In many cases, it is impossible to prevent mouth ulcers, as they are often the result of things that are out of our control (such as genetics or medical conditions). However, there are steps that can be taken that may help to reduce the risk of developing mouth ulcers. These include:

• Avoiding foods that are known to be triggers, such as chocolate or spicy foods.
• Using a soft-bristled toothbrush that will help to reduce irritation in the mouth.
• Avoid using toothpaste that contains Sodium Lauryl Sulphate.
• Avoid excessively chewing gum.
• Reducing your stress and anxiety levels.
• Try to avoid chewing or biting the inside of your mouth.