This book is concerned with presenting a comprehensive review on buccal drug delivery system. This includes buccal drug delivery and its approaches to oral buccal mucoadhesive system and its evaluation of buccal drug delivery system. The blood supply to the oral cavity tissue is delivered via the external carotid artery, which branches into the maxillary, lingual and facial arteries. The advances in bioadhesive and controlled release technology have caused much interest in drug delivery through the oral mucosa.