Background: The delivery of drugs through the buccal mucosa has received a great deal of attention over the last two decades, and yet there are not many buccal delivery products available on the market. Objective: This review outlines the advantages and disadvantages of buccal drug delivery, provides a historical perspective and discusses representative developmental and marketed drugs. Methods: The structure of the oral mucosa is briefly described to preface a description of the pathways for drug absorption and a critical discussion of permeation experiments. A brief historical perspective followed by a description of some of the currently marketed products provides a picture of where we are today. An indication is given of likely progress in this area and of the attributes of a successful business entity of the future. Conclusion: The authors provide an assessment of the future potential of buccal and sublingual drugs.