Counterstains in the direct and indirect immunofluorescence methods may be used to reduce or eliminate background nonspecific staining or autofluorescence and to increase cellular and tissue detail. The advantages and disadvantages of a number of such counterstains in terms of (a) elimination of background fluorescence, (b) blocking of specific staining, (c) cellular detail and (d) rapidity of fading are discussed, and a new method of counterstaining nuclei with methyl green is presented. Methyl green counterstain is the procedure of choice when maximal cellular and tissue detail is desired. The lissamine-rhodamine-conjugated bovine serum albumin and eriochrome black methods are especially useful in reducing or eliminating nonspecific staining and tissue autofluorescence.