Crystal violet or gentian violet (also known as methyl violet 10B or hexamethyl paraaminobenzoyl chloride) is a triarylmethane dye used for histological staining and classification of Gram bacteria. Crystal violet has antibacterial, antifungal, and insect repellent properties and was previously important as a topical preservative. Although the dye is still listed by the World Health Organization, its medical use has been largely replaced by more modern drugs. Gentian violet was originally named for a mixture of methyl-p-nitroaniline dye (methyl violet), but is now often considered a synonym for crystal violet. The name refers to its color, just like the petals of some gentian flowers. It is not made from gentian or violet.
