A common type of mouth sore is an ulcer. Mouth ulcers can be caused or triggered by:

• stress or anxiety hormonal changes
• any injury or damage to the mouth, such as from sharp teeth, dentures, or braces
• a reaction to certain foods, drugs or toothpastes
• some infections and diseases
• certain medications and medical treatments
• vitamin deficiencies.

Mouth ulcers are usually round and white/pink in colour and usually occur inside the lips, inside the cheeks, on the bottom of the mouth or under the surface of the tongue.

Mouth sores will usually only last a couple of weeks, especially if treated. However, if your mouth sores last longer than this, it may be a sign of a more serious problem.

Check your symptoms with healthdirect’s Symptom Checker to get advice on when to seek medical attention.

Looking after yourself

It’s important to treat mouth ulcers properly to help the healing process. If after following this advice they do not get better, contact your doctor.

• Try not to touch the sore area. Not only will this disturb the healing process but it could also cause an infection to spread. If you do need to touch the area, make sure you wash your hands before and after.
• Use a soft toothbrush to clean your teeth. If your sores are so painful that you can’t brush your teeth, use a mouthwash containing chlorhexidine instead. This should be available from your local pharmacy and some supermarkets. Avoid using mouthwashes that contain alcohol.
• Salt water may help. Mix one teaspoon of salt into a cup of water, then take a mouthful of the liquid and hold it in your mouth so it covers the affected area for two minutes, then spit it out. Do not swallow it. Repeat four times a day.
• Avoid hard foods that could rub against your mouth sore. You should also try to avoid chocolate, coffee, peanuts, almonds, strawberries, cheese and any salty foods because they may make mouth sores worse.
• Avoid overly hot foods and drinks.
• Drinking cool water can help to ease a painful mouth.
• If your mouth is really sore, drinking through a straw can help.
• Eat well. Choose fruit and vegetables that have a high vitamin C content and whole grain foods that are high in vitamin B. Seafood and iron rich foods, such as leafy green vegetables, are also recommended.
• You can soothe any pain or discomfort with anaesthetic lozenges you can get from your local pharmacy. There are also treatments designed for mouth ulcers, but remember to always speak to a pharmacist before buying anything.
• If you are in pain, get advice on pain relief medicines you can take.