Gentian violet (crystal violet) was used in the past to treat oral and nipple thrush during breastfeeding. Gentian violet is potentially toxic to the mucous membranes, causing oral ulceration with partial airway obstruction in one case,[1-6] and potentially tattooing the skin. It can also interact with DNA,[7] is carcinogenic and mutagenic in animals, and occasionally causes allergic sensitization, with cross-reactions to other triphenylmethane dyes.[8] Its use has been severely curtailed by authorities in Australia, Canada, England and France.[9-11] It is also very messy, staining skin and clothing. A 2001 survey of the members of the Academy of Breastfeeding Medicine (ABM) found that gentian violet is rarely (1 to 2% of respondents) used by breastfeeding experts for initial treatment of oral thrush and is very infrequently (3 to 4% of respondents) used for recurrent or persistent thrush.[10] ABM guidelines for treating Candida infection of the nipples state that an aqueous solution of gentian violet of less than 0.5% can be used for no more than 7 days on the nipple.[9] However, safer alternatives for treating thrush are available.[12]