Known medically as aphthous stomatitis, canker sores are painful ulcers of the oral cavity. Canker sores can appear on the tongue, gums, soft palate or inside the lip or cheek. Most canker sores are little more than nuisances, but some can make talking, chewing and swallowing painful.

The exact cause of canker sores is unknown but doctors know that canker sores aren't contagious and, unlike cold sores, which are just herpes infections of the lip, canker sores don't seem to be virus-based. However, canker sores do seem to be related to gluten sensitivities, mouth injury and a depressed immune system.

There is some evidence that Sodium Lauryl Sulfate, a foaming agent commonly used in oral care products, may play a role in canker sore outbreaks. Sodium Lauryl Sulfate, or SLS, encourages sloughing of the oral mucosa and dries the protective barrier of the mouth, allowing the more delicate tissue underneath to become damaged.

Most canker sores clear on their own within about three weeks but you can speed the healing process a bit by using the over-the-counter medication Debactoral. Though it isn't really a "natural" cure, Debactoral will chemically cauterize the area, reduce or eliminate pain, and cut the healing time down to about a week. Of course, if you experience a canker sore that just won't heal or one that seems to be getting worse instead of better, your doctor can advise you on the best course of treatment.

For a natural approach to canker sores, prevention seems to be the key. Canker sores are strongly linked to deficiencies of thiamin, iron, zinc, folic acid and B12. In addition to increasing your intake of the leafy greens known to be high in these nutrients, your health care provider may also test you for gluten sensitivity. Some gluten-sensitive patients have reported a complete remission of canker sores simply by eliminating this common allergen. Additionally, a round of probiotics, benefical bacteria capsules that can be purchased at any natural foods store, may be helpful for some people.

Alum, slippery elm and deglycyrrhizinated licorice (DGL) are popular natural treatments. Purchase these products at any large health food store, grind them into a powder and add just enough water to make a thin paste. Apply the paste directly to the sore.