Histology, cytology and other related scientific disciplines study the microscopic anatomy of tissues and cells. In order to demonstrate a good tissue and cellular structure, the samples need to be stained in a correct manner. Alcian Blue is used to prove glycosaminoglycan in mucins, for staining amyloids, cysteines and for polychromatic staining of mastocytes according to Blue-Safranin. It is also used to determine bacterial species and detecting bacterial capsules. Combining P.A.S. staining and Alcian Blue dye improves the identification of acid mucosubstances (glycosaminoglycan). The sample is treated with periodic acid and Schiff reagent that stains aldehydes recognizably red.