Methylrosanilinium (Gentian Violet) is a deep-violet synthetic dye belonging to the triarylmethane group, long used in medicine, microbiology, and staining techniques. First synthesized in the late 1800s, it quickly gained importance because of its intense color and strong antimicrobial properties. Historically, it became a cornerstone of the Gram-staining method, where it allows clear differentiation of Gram-positive bacteria, and it was also used as an accessible topical antiseptic for wounds, skin infections, and fungal conditions like oral thrush. Although its routine medical use has declined with the advent of modern antimicrobials, methylrosanilinium continues to hold value in laboratory staining, certain veterinary applications, and niche clinical uses due to its effectiveness, stability, and low cost.
