Amlexanox is an ant allergic drug, clinically effective for atopic diseases, especially allergic asthma and rhinitis. Amlexanox as a topical paste is a well-tolerated treatment of recurrent aphthous ulcers. Recurrent aphthous ulcer (RAU) is the most prevalent oral mucosal disease in humans, estimated to affect between 5% and 50% of the general population. The mechanism of action by which amlexanox accelerates healing of aphthous ulcers is unknown. In vitro studies have demonstrated amlexanox to be a potent inhibitor of the formation and/or release of inflammatory mediators (histamine and leukotrienes) from mast cells, neutrophils and mononuclear cells. Given orally to animals, amlexanox has demonstrated anti-allergic and anti-inflammatory activities and has been shown to suppress both immediate and delayed type hypersensitivity reactions. The relevance of these activities of amlexanox to its effects on aphthous ulcers has not been established. Amlexanox inhibits chemical mediatory release of the slow-reacting substance of anaphylaxis (SRS-A) and may have antagonistic effects on interleukin-3. When cells are under stress, they release an inactive form of human fibroblast growth factor 1 (FGF-1), a potent mitogen (entity that causes mitosis). Amlexanox binds to FGF1, increasing its conformational stability, sterically blocking Cu(2+) induced oxidation which normally leads to activation of FGF-1. This drug has been discontinued in the U.S