BioGnost’s Hematoxylin H is a well-known formulation of hematoxylin used in histopathology for a more precise nuclear cell staining. Hematoxylin acc. to Harris is applied using a regressive method in a routine hematoxylin and eosin (HE) staining in histology. Hematoxylin is extracted from logwood (Haematoxylon campechianum L.). Hematoxylin oxidizes to hematein and binds with metal ions (mordants), hematein turns into irreplaceable nuclear color. Positively charged hematein-mordant complex then binds with negatively charged phosphate ions of the DNA’s nucleus, creating characteristic blue coloration. The original Hematoxylin acc. to Harris formula is oxidized with mercury oxide. However, BioGnost’s version of Hematoxylin acc. to Harris does not contain mercury oxide because of its toxicity; environment-friendly sodium or potassium iodate is used instead. Hematoxylin H stains nuclear membrane, nucleoplasm and nucleolus exceptionally well.