The gallocyanin chromalaun stain according to Einarson is a histological staining method mainly used to visualize nucleic acids in cell nuclei and cell structures. The staining is based on the use of gallocyanin, a basic inorganic dye, and chromalaun (potassium aluminum sulfate), a mordant that enhances the binding of the dye to the structures to be stained.

Gallocyanin chromalaun staining by Einarson allows selective visualization of nucleic acids such as DNA and RNA in nuclei and other cellular structures. The nucleic acids are stained blue-violet, while other cellular components are usually not stained or only weakly stained.

This staining method is used in histology and cytology to examine tissue sections and cytological preparations and to analyze changes in the expression and distribution of nucleic acids under various physiological and pathological conditions.