Hematoxylin and eosin stain or haematoxylin and eosin stain (H&E stain or HE stain) is one of the principal stains in histology. It is the most widely used stain in medical diagnosis and is often the gold standard (for example, when a pathologist looks at a biopsy of a suspected cancer, the histological section is likely to be stained with H&E). A combination of hematoxylin and eosin, it produces blues, violets, and reds.