Biological products used to induce immunity to various infectious diseases or noxious substances of biological origin. The term is usually limited to immune serums, antitoxins, vaccines, and toxoids that have the effect of providing protective substances of the same general nature that a person develops naturally from having survived an infectious disease or having experienced repeated contact with a biological poison. As a matter of governmental regulatory convenience, certain therapeutic substances which have little to do with conferring immunity have been classified as biological products primarily because they are derived from human or animal sources and are tested for safety by methods similar to those used for many biological products.