Magenta Chemical formula

💊 Chemical information

Aniline Red; Basic Fuchsin; Basic Magenta; CI Basic Violet 14; Colour Index No. 42510; Fuchsine; Fucsina.


Magenta is a mixture of the hydrochlorides of pararosaniline {4-[(4-aminophenyl)(4-iminocyclohexa-2,5-dien1-ylidene)-methyl]aniline} and rosaniline {4-[(4-aminophenyl)(4-iminocyclohexa-2,5-dien-1-ylidene)methyl]-2-methylaniline}.


In US.

USP 31

(Basic Fuchsin). A mixture of rosaniline and pararosaniline hydrochlorides. It contains the equivalent of not less than 88% of rosaniline hydrochloride (C 20 H 20 ClN 3 = 337.8), calculated on the dried basis. A dark green powder or greenish glistening crystalline fragments with a bronze-like lustre and not more than a faint odour. Soluble in water, in alcohol, and in amyl alcohol; insoluble in ether.

💊 Profile

Magenta is a triphenylmethane antiseptic dye effective against Gram-positive bacteria and some fungi. Magenta Paint (BPC 1973) (Castellani’s Paint) was formerly used in the treatment of superficial dermatophytoses. Decolorised magenta solution (Schiff reagent) is used as a test for the presence of aldehydes. Concerns about possible carcinogenicity have restricted the use of magenta.


The handling of magenta was not thought to induce carcinogenesis but its actual manufacture may produce tumours. The International Agency for Research on Cancer has concluded that the manufacturing process of magenta involves exposure to substances that are considered to be definite human carcinogens. Pararosaniline hydrochloride (Basic Red 9), and magenta containing it, are considered possibly carcinogenic to humans.1 Magenta was also considered to be unsafe for use in food.2
1. IARC/WHO. Occupational exposures of hairdressers and barbers and personal use of hair colourants; some hair dyes, cosmetic colourants, industrial dyestuffs and aromatic amines. IARC monographs on the evaluation of carcinogenic risks to humans volume 57 1993. Available at: Monographs/vol57/volume57.pdf (accessed 23/05/06
2. FAO/WHO. Specifications for the identity and purity of food additives and their toxicological evaluation: food colours and some antimicrobials and antoxidants: eighth report of the joint FAO/WHO expert committee on food additives. WHO Tech Rep Ser 309 1965. Also available at: WHO_TRS_309.pdf (accessed 28/08/08)

💊 Preparations

BPC 1973: Magenta Paint; USP 31: Carbol-Fuchsin Topical Solution. Proprietary PreparationsMulti-ingredient: Ital.: Fucsina Fenica; Pol.: Pigmentum Castellani.
Published January 16, 2019.