Harris' hematoxylin is a commonly used alum hematoxylin that may be used for progressive staining of cytology specimens, but may also be used for staining of histology tissue sections by either progressive or regressive staining methods. The staining tends to provide clear nuclear detail. One challenge when using Harris' hematoxylin is that it is best differentiated with a mild acid, as opposed to the more commonly used hydrochloric acid-based differentiating solutions. Harris' hematoxylin is an alcohol-based stain.
