Treatment is usually not necessary. In most cases, the canker sores go away by themselves.

If you have a canker sore, you should not eat hot or spicy foods, which can cause pain. Mild, over-the-counter mouth washes or salt water may help. There are over-the-counter medicines that soothe the painful area. These medicines are applied directly to the sore area of the mouth.

The easiest home remedy is a mixture of half hydrogen peroxide and half water. Use a cotton swab to apply the mixture directly to the canker sore. Then, dab a small amount of Milk of Magnesia on the canker sore, three to four times a day. This is soothing and may also help it heal.

Another home remedy is to mix half Milk of Magnesia and half Benadryl liquid allergy medicine. Swish this mixture in your mouth for about 1 minutes, then spit it out.

Other treatments for more severe cases include applying fluocinonide gel (Lidex) or chlorhexidine gluconate mouthwash. Powerful anti-inflammatory medicines called corticosteroids are sometimes used.

To prevent bacterial infection, brush and floss your teeth regularly and visit the dentist for routine care.

Canker sores usually heal on their own. The pain usually decreases in a few days. Other symptoms disappear in 10 to 14 days.

Antibiotic treatment for canker sores may lead to oral thrush (a type of mouth infection) or other Candida infections. Rarely, bacterial infections such as cellulitis and Ludwig's angina may occur.

Canker sores are not cancer and don't lead to cancer. But if you have a mouth ulcer lasts more that 2 weeks, you should see your doctor to rule out possible cancer.

Apply home treatment and call your health care provider if symptoms of canker sores persist or worsen, or canker sores recur more often than 2 or 3 times per year.

Call your health care provider if symptoms are associated with other problems such as fever, diarrhea, headache, or skin rash.