Gentian violet (crystal violet, Methyl Violet 10B, hexamethyl pararosaniline chloride) is an antifungal agent,the primary agent used in the Gram stain test, perhaps the single most important bacterial identification test in use today, and it is also used by hospitals for the treatment of serious heat burns and other injuries to the skin and gums. Typically prepared as a weak (e.g. 1%) solution in water, it is painted on skin or gums to treat or prevent fungal infections. Gentian violet does not require a doctor's prescription (in the US), but is not easily found in drug stores. Tampons treated with gentian violet are sometimes used for vaginal applications.
Gentian violet is also known as Andergon, Aniline violet, Axuris, Badil, Basic Violet 3, Brilliant Violet 58, Gentiaverm, Hexamethyl-p-rosaniline chloride, Meroxylan, Meroxyl, Methylrosanilide chloride, Methyl Violet 10BNS, Pyoktanin, Vianin, Viocid, and Viola Crystallina. It is worth noting that the name "Gentian Violet" refers to its colour, being like that of the petals of a gentian flower; it is not made from gentians or from violets.
Commonly used for
Impetigo, before the advent of antibiotics but still useful to persons who may be allergic to penicillin, as it cleans the open sores and prevents spread of the contagion
One study has linked long term exposure to large amounts of Gentian violet with cancer  . The Food and Drug Administration in the US has determined that gentian violet has not been shown by adequate scientific data to be safe for use in animal feed. Use of gentian violet in animal feed causes the feed to be adulterated and is a violation of the Federal Food, Drug, and Cosmetic Act in the US. On June 28, 2007, the US food and Drug Administration issued an "import alert" on farm raised seafood from China because unapproved antimicrobials, including gentian violet, had been consistently found in the products. The FDA report states:
"Like MG [malachite green], CV [crystal violet] is readily absorbed into fish tissue from water exposure and is reduced metabolically by fish to the leuco moiety, leucocrystal violet (LCV). Several studies by the National Toxicology Program reported that the carcinogenic and mutagenic effects of crystal violet in rodents. It has also been linked to increased risk of human bladder cancer. The leuco form induces renal, hepatic and lung tumor in mice."
Gentian violet's worst common side effect is staining skin and cloth, but if used on ulcerations or open wounds it can cause tattooing. It is generally considered safe for use on children and breastfeeding mothers. It has even been applied to the mouth and lips of premature infants, and has a long history of safe use. Many have recommended it for thrush on the nipple, and La Leche League lists gentian violet as a possible alternative. However, in large quantities, gentian violet may lead to ulceration of a baby's mouth and throat and is linked with mouth cancer. Dr. Sears recommends using it sparingly. Gentian violet has also been linked to cancer in the digestive tract of other animals .
When using gentian in order to purple skin or jackets, care should be taken to mix only low concentrations of the crystal into warm water. This avoids the material attaining a golden hue. Additionally, jackets with a waterproof coating should be scrubbed lightly with a scrub pad, steel wool, or light grade sand paper before dyeing.
In Catch-22, the medics are portrayed as using gentian violet on feet and gums as a panacea. This may be because of the fact that in World War I American soldiers returning after a leave were irrigated with Gentian violet to prevent sexually transmitted disease.
In July 2003, the polar bear Pelusa in the Mendoza, Argentina zoo was treated with gentian violet. News stories with a picture of the purple polar bear were widely read. However, many accounts referred only to a "drug", "treatment" or "antiseptic" without naming it. This gave rise to claims that the photo was digitally altered and the story was a hoax.
Gentian violet is used by engineering students at some Canadian universities to dye skin purple during Frosh Week and Homecoming. This occurs most notably at Queens University, where engineering students will also dye their faculty jackets(GPA's), from gold, to a deep violet hue .