Mouth Ulcers

Mouth Ulcers. Mouth ulcers are painful sores that appear inside the mouth. They appear red or yellow and are not cold sores.


  • Damage caused eg Biting of cheek or tongue
  • Sharp teeth
  • tooth brushing
  • poorly fitted dentures

The above are traumatic ulcers which are usually on their own, next to the cause of the damage.

Types of ulcers

Minor ulcers are the most common. They can appear inside the cheeks, on the lips, tongue and gums and, more rarely on the roof on the mouth. Most of these ulcers are the size of the top of a pencil and can sometimes come in clusters. You can get 4 to 6 at any one time. They only last for a week or two.

Large ulcers are more severe and last for 5-10 weeks. They may appear near the tonsils and can be very painful when swallowing. You normally get one at a time.

You can get up to 100 very small ulcers which last for 1-2 weeks.

If you get ulcers in other parts of the body tell your dentist about this.


  • Have good hygiene
  • Use quality toothbrush
  • Good diet
  • Visit your dentist

Mouth cancer can first appear as a mouth ulcer. They last a long time without any obvious cause. If it lasts longer than 3 weeks you should see your dentist. Ulcers caused by cancer usually appear on or under the tongue but may appear somewhere else. For more information about Mouth cancer visit our Mouth cancer page.


  • Sharp tooth to be smoothed down
  • Denture adjustment
  • Sometimes, Mouthwashes or tablets

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