Absorption of drugs through the oral cavity was noted as early as 1847 by Sobrero, the discoverer of nitroglycerin, and systemic studies of oral cavity absorption were first reported by Walton and Lacey in 1935. As a site for drug delivery, the oral cavity offers many advantages over other routes of drug administration. The mucosal lining of the oral cavity are readily accessible. During the chewing process, most of the medications contained within the gum product are released into the saliva and are either absorbed through the buccal mucosa or swallowed and absorbed through the gastrointestinal tract. Delivery systems containing actives for oral administration now include various chewing gum formulations. Chewing gums permit release of the active ingredient over time as the gum product is masticated, or chewed. The action of saliva on the gum further facilitates release of the active, as well as its subsequent absorption by the mucous membranes lining the mouth, throat, larynx and esophagus.