The May-Grünwald′s eosin methylene blue staining dye for microscopy, is used to make a stain that is frequently used for diagnostic purposes in the area of hematology. When used in hematological applications, May-Grünwald′s stain is frequently used in combination with other staining solutions, e. g. with Giemsa′s solution for Pappenheim (MGG) overview staining. This staining solution generally stains the nuclei red to violet, based on the molecular interaction between the Eosin Y dye and an Azure B-DNA complex. Both dyes assemble to an Eosin Y - Azure B-DNA complex and the intensity of the resulting stain depends on the content of Azure B and the ratio of Azure B : Eosin Y. Furthermore, the resulting stain can vary depending on the influence of fixation, staining times, pH-value of the solutions or buffer substances.