Eosinophilic is a technical term used by histologists. The context in which this word is used is in describing the microscopic appearance of cells and tissues, as seen down the microscope, after a histological section has been stained with the dye eosin.

Eosinophilic describes the appearance of cells and structures seen in histological sections which take up the staining dye, eosin. This is a bright pink dye that stains the cytoplasm of cells as well as extracellular proteins such as collagen.

Such eosinophilic structures are generally composed of protein.

The stain eosin is usually combined with a stain called haematoxylin to produce a haematoxylin and eosin stained section (also called an H&E, HE or H+E section). This is the most widely used histological stain in medical diagnosis - for example when a pathologist looks at a biopsy of a suspected cancer they will have the section stained with H&E

Some structures seen inside cells are described as being eosinophilic, for example LEWY BODY , MALLORY BODY.

See also basophilic.