The exact cause of mouth ulcers is still not known and varies from person-to-person. Still, there are some common causes and several factors that may aggravate mouth ulcers, including the following:        

  • Quitting smoking     
  • Citrus fruits and other foods high in acidity or spice 
  • Biting the tongue or inside of the cheek        
  • Braces, poor-fitting dentures, and other apparatus that may rub against the mouth and gums·        
  • A deficient filling        
  • Stress or anxiety      
  • Hormonal changes during pregnancy, puberty, and menopause      
  • Medications including beta-blockers and pain killers     
  • Genetic factors

Some people may develop ulcers as a result of a different medical condition or a nutritional deficiency. Conditions such as celiac or Crohn's disease, vitamin B12 or iron deficiency, or a weakened immune system may all trigger ulcers to form.

Are mouth ulcers cancerous?

Mouth cancer and mouth ulcers are distinctive in their symptoms. However, as mentioned earlier, new or persistent ulcers require checking.

There are some fundamental differences between mouth ulcers and what might be cancer:

Mouth ulcers are often painful whereas mouth cancer is not.   

Mouth ulcers will clear up in about 2 weeks, whereas mouth cancer will not go away and will often spread.

Mouth cancer patches may be rough, hard, and not easy to scrape off.       

Mouth cancer is often a mix of red and white areas or large white areas that appear on the tongue, the back of the mouth, the gums, or on the cheeks.

Mouth cancer is often linked to heavy drinking or tobacco use. 


In many cases, the pain and discomfort from mouth ulcers will lessen in a few days and then disappear in about 2 weeks with no need for treatment.For people with much more painful or frequent recurrence of mouth ulcers, a dentist may prescribe a solution to reduce swelling and lessen pain. Also, a dentist may prescribe an antimicrobial mouthwash or an ointment to be applied directly to the infected patch. This can help to ease discomfort.