Eosin Y (C.I. 45380)

Eosin Y also called C.I. 45380 or C.I. Acid Red 87, is the form of eosin most commonly used in histology, most notably in the H&E (Haematoxylin and Eosin) stain. Eosin Y is also widely used in the Papanicolaou stain (or Pap stain used in the Pap test) and the Romanowsky type cytologic stains.