At first glance, canker sores seem like a trivial complaint. These small sores inside the mouth aren't life-threatening or contagious. They don't leave a scar and usually go away within a week. What's the big deal? The problem is that many people have recurrent canker sores that occur several times a month. Because the nerves in the mouth are so sensitive, canker sores, which occur on the tongue, inside the cheek and/or behind the lips, cause a lot of pain. If you have recurrent canker sores, it can be extremely painful to eat—or even speak. Unlike cold sores, which are triggered by the herpes simplex virus and can be treated with antiviral medications, most canker sores result from a localized immune reaction brought on by stress, a food allergy, nutritional problems or trauma, such as biting your tongue or lip. If you have recurrent canker sores…

  • Consider allergy testing. You may develop a canker sore because your mouth becomes irritated within a matter of hours of eating a highly acidic meal that includes tomatoes, citrus or chocolate—or after drinking coffee, black tea or carbonated beverages. With a food allergy, the reaction may not occur for several hours or it may be immediate. If you get recurrent canker sores, it's wise to get an immunoglobulin G (IgG) food allergy blood test to identify the specific foods that weaken your immune system and trigger an allergic reaction. If it's not convenient for you to get allergy testing, try avoiding the most common offending foods one at a time for one week each to identify those that trigger an allergic reaction in you. In my practice, wheat, garlic, nuts, soy and citrus are the most frequent allergens among canker sore sufferers.
  • Check for a nutritional deficiency. If you have a deficiency of vitamin B-12, the B vitamin folic acid or iron, you are likely to develop recurrent canker sores. Even if you already take a daily multivitamin, you can safely add 600 micrograms (mcg) in supplemental folic acid and an 800-mcg supplement of vitamin B-12 daily. Try these supplements for one month to see whether they are effective.

Caution: Be sure to get your iron levels tested if you suspect an iron deficiency. Taking an iron supplement unnecessarily can lead to liver damage.

  • Take precautions if you're under stress. Stress leads to canker sores because it reduces digestive function, decreases immune health and increases inflammation. If you are prone to canker sores, add more bland foods, such as brown rice, baked potatoes, lightly steamed vegetables, poultry and fish, to your diet when you're under stress. Bland foods are easier to digest and less likely to irritate the mouth and digestive tract.
  • Use herbal remedies. If you develop a canker sore, you can speed healing by taking two slippery elm capsules every four hours on an empty stomach. In addition, drink three cups of licorice root tea daily. Both these herbs moisten and soothe the mucous membranes of the mouth and digestive tract.

Caution: if you have high blood pressure, avoid licorice—which can adversely affect blood pressure in some people.

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