BioSchiff reagent is a colorless solution that changes to violet (magenta) in the presence of aldehydes. The intensity of the color obtained depends on the number of reactive glycol structures in the tissue. It is prepared by the reduction of pararosaniline by using sulfuric acid. Schiff’s reagent is used with various chemical methods, and one of the most common and most widely used ones is P.A.S. staining (Periodic Acid Schiff). The P.A.S. staining is based on the oxidation reaction with the presence of periodic acid and Schiff’s reagent. Periodic acid makes the molecules containing glycol groups create aldehydes affected by Schiff’s reagent that stains them violet (magenta). This method is most commonly used in liver and muscle cells testing. Schiff’s reagent can be used for DNA detecting according to Feulgen.