Freund’s Adjuvant is widely used in immunology research to enhance the immune response to antigens. It is particularly valuable in the production of polyclonal antibodies in laboratory animals. The adjuvant works by creating a depot effect at the injection site, allowing for the slow release of the antigen and prolonging exposure to the immune system. This results in a stronger and more sustained immune response. Complete Freund’s Adjuvant, which contains inactivated mycobacteria, is typically used for the initial immunization to stimulate a robust immune reaction. Incomplete Freund’s Adjuvant, lacking mycobacteria, is used for subsequent booster injections to maintain the immune response without excessive inflammation. Its application is critical in vaccine development, immunological studies, and the generation of antibodies for diagnostic and therapeutic purposes. However, due to its potential to cause significant inflammation and tissue damage, its use is restricted to animal research and not approved for human vaccines.