AbstractAn alternative to picric acid as a mordant in the staining of cytoplasm, keratin, muscle fibers, and intercellular fibers in the Masson trichrome stain is a citrate acid-sodium citrate buffer used as the microwave pretreatment of the tissue mounted on a slide. The Masson trichrome stain, a combination of Biebrich scarlet-acid fuchsin and aniline blue dye can be done within 1 hr and avoids the hazards associated with picric acid, a highly explosive compound in the dry state. (The J Histotechnol19:341–342, 1996)