The use of biologicals for clinical use is rapidly increasing. One of the logical questions is what constitutes a biological? The official definition of biological products by the Food and Drug Administration is “Biological products can be composed of sugars, proteins, or nucleic acids, or a combination of these substances. They may also be living entities, such as cells and tissues. Biologics are made from a variety of natural resources—human, animal, and microorganism—and may be produced by biotechnology methods.”