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Canker sores

What is it?

Canker sores are also called aphthous (af-thus) ulcers. They are sores inside the mouth. You may have canker sores on the inside of your lips and cheeks or on your gums or tongue. It is common to have more than one. They are painful but not harmful. Usually, canker sores heal in 2 weeks. You may get them more than once.


It is not known what causes canker sores. Some causes may be stress or an infection (in-fek-shun). Changes before a woman's monthly period can cause canker sores. Certain foods, such as pickles or potato chips, seem to cause canker sores in some people. Rough dentures, braces, or teeth brushing may also cause canker sores.

Signs and Symptoms:

You may have small, painful, white-colored sores that are circled in red. It may hurt to eat or speak for a few days.

Medical Care:

There is no cure for canker sores. Sometimes medicines are used to help your pain. Follow your caregiver's advice for caring for your mouth. You may need to have your dentures or braces adjusted if they are causing the sores.

Dietary Measures:

  • Eat a healthy and well-balanced diet rich in vitamins and minerals.
  • Keep a food and symptom diary to learn if certain foods trigger a canker sore.
  • Avoiding toothpaste with sodium lauryl sulfate (SLS) may be helpful.

Herbs and Supplements:

Before taking any herbs or supplements, ask your caregiver if it is OK. Talk to your caregiver about how much you should take. If you are using this medicine without instructions from your caregiver, follow the directions on the label. Do not take more medicine or take it more often than the directions tell you to. The herbs and supplements listed may or may not help treat your condition.



      Complementary Therapies:

      • Relaxation techniques may help prevent canker sores.

      Other ways of treating your symptoms : Other ways to treat your symptoms are available to you.

      Talk to your caregiver if:

      • You would like medicine to treat canker sores.
      • Your symptoms have not gone away or improved by these self-help measures.
      • You cannot eat or drink because of the pain.
      • You get more than four canker sores at a time.
      • The sores are not better in 5 to 6 days.
      • You have questions about what you have read in this document.

      Care Agreement:

      You have the right to help plan your care. To help with this plan, you must learn about your health condition and how it may be treated. You can then discuss treatment options with your caregivers. Work with them to decide what care may be used to treat you. You always have the right to refuse treatment.


      1. Chahine L, Sempson N &Wagoner C: The effect of sodium lauryl sulfate on recurrent aphthous ulcers: a clinical study. Compend Contin Educ Dent 1997; 18(12):1238-1240.

      2. Das SK, Das V, Gulati AK et al: Deglycyrrhizinated liquorice in aphthous ulcers. J Assoc Physicians India 1989; 37(10):647.

      3. McCartan BE, Lamey PJ & Wallace AM: Salivary cortisol and anxiety in recurrent aphthous stomatitis. J Oral Pathol Med 1996; 25(7):357-359.

      4. Nolan A, Lamey PJ, Milligan KA et al: Recurrent aphthous ulceration and food sensitivity. J Oral Pathol Med 1991; 20(10):473-475.

      5. Wray D: Nutritional deficiencies in recurrent aphthae. J Oral Pathol 1978; 7:418-423.

      Last Updated: 12/4/2015

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