Subsequent to immunohistological procedures, counterstaining of tissue sections is helpful for the study of histological and histopathological details. An effective counterstain should not intrude the major stain, i.e. the immunostained antigen in the tissue section. The right selection of a counterstain will result in important additional information. In most cases, the overall morphology of the tissue section or the staining of nuclear morphology is desired. Since the introduction of haematoxylin (from the logwood Haematoxylon campechianum, a tree indigenous to Central America and prepared by several extraction and precipitation methods) as histological stain, many staining formulations have been suggested. Examples of the enduring haematoxylin staining methods are given.