The hexazonium pararosaniline kit, frequently used in medical diagnostics, is particularly suitable for staining blood and bone marrow samples. Applications are mainly found in histology and life sciences, where it is used to visualize chloroacetate esterase in cells. Thanks to its special composition, which includes pararosaniline, hydrochloric acid, sodium nitrite and aqua bidest, the kit offers high staining quality. In the chemical context, pararosaniline is characterized by its triphenylmethane structure and is sensitive to pH changes, which explains its staining capacity. The reaction of pararosaniline with hexazonium salts leads to the formation of a stable dye complex that binds to chloroacetate esterase. This binding allows precise identification and characterization of cells, making the kit an indispensable tool in medical diagnostics.