Recurrent aphthous stomatitis (RAS) is accepted as one of the most common diseases involving human oral tissues. They are painful, small ulcers in the mouth or on the inner lips caused by an assortment of viruses. Doctors call this condition aphthous stomatitis, aphthous ulcers or canker sores. They can appear on the tongue, the lips, the gums or the insides of the cheeks. The first sign of a canker sore may be a tingling, burning sensation inside the mouth, followed shortly by the appearance of a white or yellowish spot edged by a red halo. Canker sores do not form blisters as cold sores (fever blisters) do. The cold sore, commonly confused with the canker sore, is caused by the herpes simplex virus. The canker sore, on the other hand, is an inflammation rather than an infection. Canker sores may range in size from the size of a pinhead to as large as a quarter. They are usually about an eighth of an inch in diameter-the size of a pencil eraser. They appear suddenly and often leave suddenly, usually lasting from four to twenty days.

Canker sores often pop up when you're under stress or after you've eaten an irritating food (pineapple, nuts and chocolate are common culprits). A susceptibility to canker sores tends to run in families. No successful conventional treatment is available. The natural remedies may help relieve the symptoms of canker sores or may prevent sores from recurring.

One strategy to try is avoiding toothpaste that contains sodium lauryl sulfate because it breaks up a protective barrier on the teeth and gums, which results in a greater frequency of ulcers. The frequency was reduced in one study by 67%. It is hard to find a toothpaste without it, but people with canker sores should make the effort if the problem does not resolve by other means. Weleda pharmacy in New York manufactures such a toothpaste.