The dentifrice today fulfills three major functions: removal of stain from the teeth by abrasive action; refreshment and cleaning of the oral cavity by virtue of flavor content and cleansing agents; and acting as a vehicle for the delivery of special therapeutic or cosmetic agents. In its broadest interpretation, then, a simple mixture of dental abrasive, flavor, and surfactant (and special agents, if desired) constitutes a dentifrice. In essence, a toothpowder is a full-fledged dentifrice. Consumers, however, prefer toothpaste to toothpowder or to other dentifrice forms. One consequence is that toothpastes have advanced from rudimentary mixtures of basic functional materials to highly sophisticated products with unique compositions, appearance, dispensing properties, and manufacturing concerns. This chapter is not intended to chart advances in toothpaste technology from early, crude products to today's technically advanced products; rather, it describes the scientific principles and technology governing today's state-of-the-art toothpastes.