Hematoxylin and eosin staining is one of the most common method used in histology and anatomy. Basophilic nuclei, bacteria, calcium, and so on are stained "blue" with hematoxylin. Eosinophilic cytoplasm, connective, and all other tissues are counterstained "red" with eosin. Hematoxylin and eosin staining is often used to detect inflammation or to determine the integrity of a tissue.
