Millions of people suffer from the painful mouth ulcers called aphthous stomatitis. Although many causes are known, and there are few effective treatments. A blister forms in the mouth and the top is quickly sloughed off, leaving a punched out whitish circular area that hurts to touch, particularly when food is in the mouth. Among the causes are infections including herpes, cytomegalovirus, yeast, and other viruses that have not even been characterized. They can also be caused by an autoimmune reaction in which a person’s own immunity causes the blister to form. It has also been reported an allergy to chemicals in toothpastes and mouth washes. No studies have isolated bacteria or virus often enough to blame them. Canker sores are a type of mouth ulcer. Some of the medical terms used to refer to canker sores are recurrent minor aphthous ulcers and recurrent minor aphthous stomatitis. Canker sores are the most commonly occurring type of mouth ulcers. Canker sores are thought to form when