Mayer's hematoxylin is a ready-made dye for histology and cytology based on hematein with a low concentration of the main substance (hematoxylin). Consists of hematoxylin, alum and potassium iodic acid.
 Does not repaint preparations, while providing excellent color intensity in sections. Allows to carry out subsequent manipulations with eosin without bluing procedure in tap water or alkaline solutions. It can be used for staining cell nuclei in cytological preparations. It is often used in immunohistochemistry and cytochemistry for counterstaining. The recommended staining time is 5-20 minutes.