Immunohistochemistry (IHC) is the commonest application of immunostaining. It involves the method of selectively identifying antigens (proteins) in cells of a tissue section by exploiting the principle of antibodies binding specifically to antigens in biological tissues. IHC takes its name from the roots "immuno", in regard to antibodies utilized in the procedure, and "history", meaning tissue (compare to immunocytochemistry). Albert Coons conceptualized and first implemented the procedure in 1941.

Visualizing an antibody-antigen interaction is often accomplished during a number of the way, mainly either of the subsequent Chromogenic immunohistochemistry (CIH), wherein an antibody is conjugated to an enzyme, such as peroxidase (the combination being termed immunoperoxidase), which will catalyze a color-producing reaction.