treat canker sore

How to treat canker sores?

Written by: WellCome Care Editorial Team

In A Nutshell:

  • Canker sores are common names given to Recurrent Aphthous Stomatitis, RAS, or simply, Aphthae
  • These sores can be treated with the topical application of corticosteroids, antiseptic/anti-inflammatory agents, and local anesthetics
  • Drugs should be used based on the severity of the sores, the intensity of the pain/discomfort and the responsiveness to treatment

Canker sores are characterized by small red bumps inside the mouth, along the soft tissues/mucosa of the lips and cheeks, which may burst open to reveal shallow pale or white lesions.

They are usually only half an inch in size, or smaller, and are quite painful. They are not contagious.

The condition is fairly common in the US and is seen in young men and women between the ages of 10 and 25. It can however, affect older age groups as well.

Unfortunately, the exact cause of canker sores is still not know. Their development has been associated with family history, stress, allergies, oral injuries, nutritional and immune system imbalances, and using Sodium Lauryl Sulphate (SLS) mouthwashes/toothpastes.

Diagnosis of canker sores is made on the basis of their symptoms and appearance. They can be mild, moderate or severe, and the duration of these lesions in the mouth depends upon their severity.

It is usually the pain that comes with having Aphthae in the mouth that is the biggest source of concern for patients. Here are a few things you can do to minimize the discomfort till they resolve:

  • Avoid acidic and spicy foods.
  • Avoid hard foods which can cause irritation to the wound
  • Use a mild toothpaste that does not contain SLS
  • Use gentle brushing strokes to avoid scratching against the wound
  • Keep applying the topical medication daily for best results


Mild to moderate sized canker sores respond well to topical treatments and usually disappear within 10-14 days. Here’s how you can treat your canker sores at home:

  • Make sure there is no food in your mouth when you apply medication
  • Wash and dry your hands
  • Clean and blot the area around the sores dry with a paper towel
  • Dispense a small amount of the medication on to a cotton swab or a Q-tip, and gently apply it over the sores
  • Try not to eat or drink anything for at least half an hour after you’ve applied the medication

If the sores respond well to the treatment, you should notice:

  • Normalization of the soft tissue color
  • Reduction in pain and discomfort
  • Reduction in size of the lesion
  • Reduction in functional impairment


Recurrent Aphthous Stomatitis, also known as canker sores, respond very well to topical agents including anti-inflammatory/antiseptic medications, corticosteroids, and mild anaesthetics. If these topical drugs are used regularly for at least 7-10 days, patients will experience a complete resolution of symptoms with pain relief and normalization of the affected oral mucosa/soft tissues.

In combination to the application of the drug, it is important to avoid spicy, acidic or hard foods that can worsen the pain and symptoms. The sores are very sensitive and must be taken care of till they completely resolve, otherwise they can reappear, or take much longer to respond to medication.


Topical gel formulations are highly effective in treating minor recurrent aphthous stomatitis, or canker sores.


  1. American Academy of Oral Medicine: Canker Sores
  2. BMC Oral Health Study - Canker sores and topical gel
  3. Epidemiological study of canker sores
  4. Study: The treatment of chronic recurrent canker sores
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