Fuchsin Acid reagent is used as a component of the Mallory Trichrome kit. Mallory trichrome staining kit is used for treating the tested microscopic sample using three different stainings with differential counterstaining of two basic parts of the tissue (muscle and collagen fibers) in focus. By staining the sample with Fuchsin Acid acidic dye nuclei and muscles are stained red to pink. The phosphotungstic acid molecule then pushes out Fuchsin Acid dye molecules from collagen and thus enables Aniline Blue to bind, resulting in collagen being stained contrast blue in relation to previously used red dye. Orange G (molecule of the lowest molar mass) stains erythrocytes.