Acid Red 87,[2][1] is a member of the triarylmethane dyes.

It is commonly used in histology, most notably in the H&E (Haematoxylin and Eosin) stain.

[1] Eosin Y is also widely used in the Papanicolaou stain (or Pap stain used in the Pap test) and the Romanowsky type cytologic stains.

[1][2] It is also used as a photosensitizer in organic synthesis.

This article about a ketone is a stub.