Cresyl violet is an organic compound with the chemical formula C19H18ClN3O.

Cresyl violet is an effective and reliable stain used for light microscopy sections.

Initially, tissue sections are "defatted" by passing through graded dilutions of ethanol.

[1] Intestinal mucins also take up the stain although not as strongly as Campylobacter-like organisms.

In this role it is also often used as a counterstain to Luxol fast blue, which stains the myelin.