Mouth ulcers are painful sores that appear in the mouth. They’re uncomfortable but they’re usually harmless. Most clear up by themselves within 1 to 2 weeks.
Mouth ulcers are common and can usually be managed at home, without seeing your dentist or GP.
Mouth ulcers are usually round or oval sores that commonly appear inside the mouth on the:
They can be white, red, yellow or grey in colour and swollen.
You may have more than one mouth ulcer at a time and they may spread or grow.
Mouth ulcers shouldn’t be confused with cold sores, which are small blisters that develop on the lips or around the mouth. Cold sores often begin with a tingling, itching or burning sensation around your mouth.
They can give you advice and treatment.
If you have a dental problem you should always phone your dentist first. If you’re not registered with any dental practice then you should read our advice on dental emergencies.
Your pharmacist may advise that you see your GP or dentist if:
Mouth ulcers are also a possible symptom of hand, foot and mouth disease. Speak to your GP or phone 111 if you’re unsure.
Most mouth ulcers clear up by themselves within 1 to 2 weeks without treatment.
However, treatment can help to reduce swelling and ease any discomfort. This may help if you keep getting mouth ulcers or your mouth ulcer affects eating and drinking.
There are things you can do to speed up healing.
You can get several types of mouth ulcer treatment from a pharmacy. Speak to your pharmacist about the best treatment for you.
A GP or dentist may prescribe stronger medicine to treat severe, persistent or infected mouth ulcers.
Possible treatments include:
In many cases, the reason for mouth ulcers is unclear. Most single mouth ulcers are caused by damage to the lining inside of the mouth. For example:
It’s not always clear what causes mouth ulcers that keep returning, but triggers are thought to include:
Your genes are also thought to have a role. Around 40% of people who keep getting mouth ulcers report that it runs in their family.
Mouth ulcers can sometimes be caused by certain medical conditions, such as:
Mouth ulcers can sometimes be caused by certain medications or treatments, such as:
In a few cases, a long-lasting mouth ulcer can be a sign of mouth cancer. If mouth cancer is detected early, the chances of a complete recovery are good. Regular dental check-ups are the best way to detect the early signs.
Last updated:
20 October 2023