Functional Dairy Products Dairy products form the major part of functional foods. To understand their success it is important to know that milk is a natural and highly nutritive part of abalanced daily diet. Designing and developing functionality in dairy-based products simply means modifying and/or enriching the healthy nature of the original base.This chapter is a brief introduction to the composition of milk and the nature offermented milk products. It also gives a few definitions and introduces some of the functional dairy products on the market. The purpose of this chapter is not to evaluate the quality and depth of the science behind each product: some of these products are tested in their final state, while the functionality of others is based on accepted knowledge of a particular compound. At the same time, this chapter offers some ¡®good guesses¡¯ as to the potential development of functional dairy foods in the future.