Synonyms: 3-Hydroxy-4-(2-sulpho-4-[4-sulphophenylazo]phenylazo)-2,7-naphthalenedisulphonic acid sodium salt, CI 27195, Ponceau, 3-Hydroxy-4-((2-sulpho-4-((4-sulphophenyl)diazenyl)phenyl)diazenyl)naphthalene-2,7-disulphonic acid, tetrasodium salt