Mouth ulcers are painful round or oval sores that form in the mouth, often on the inside of the cheeks.
Although mouth ulcers can be uncomfortable, especially when you eat, drink or brush your teeth, they are harmless.
Most mouth ulcers clear up by themselves within a couple of weeks. You only need to see a doctor if the ulcer gets worse or lasts for longer than three weeks.
Read more about the symptoms of mouth ulcers.
How common are mouth ulcers?
Mouth ulcers, which are also known as apthous ulcers, are very common. Most people will have at least one during their lifetime. They're particularly common in women and young adults.
Mouth ulcers can't be passed from person to person. For example, you can't get an ulcer from kissing someone or from sharing drinking glasses or cutlery.
Recurrent mouth ulcers
Most people only have mouth ulcers occasionally. However, some people find they keep coming back. These are called recurrent mouth ulcers.
In the UK, one in five adults and about 5%-10% of children suffer from recurrent mouth ulcers.
Recurrent mouth ulcers are often different from those that cause single ulcers. See the causes of mouth ulcers for more information.
How to treat mouth ulcers
Mouth ulcers usually get better by themselves, but there are some self-help measures and medications that can be useful for troublesome ulcers.
Read more about the treatment of mouth ulcers.
One way to prevent getting mouth ulcers in the first place is to make sure you look after your teeth and gums. Find out more about how to look after your dental health and other ways to prevent mouth ulcers.
