Complete Freund's adjuvant (CFA) is an immunologic adjuvant emulsified with antigens, composed of heat-killed, inactivated Mycobacterium tuberculosis in a water-in-oil emulsion with paraffin oil. As a TLR ligand, it enhances the immune response to antigens in animals, induces Th1-type immune responses, and is commonly used to establish experimental models such as rheumatoid arthritis, persistent inflammatory pain, and experimental autoimmune myocarditis (EAM) in rats.