CheckVegan

Is Direct Red 28 vegetarian?

Direct Red 28

Vegetarian Vegetarian
Vegan Vegan

Congo Red is a synthetic azo dye and the sodium salt of 3,3′-([1,1′-biphenyl]-4,4′-diyl)bis(4-aminonaphthalene-1-sulfonic acid). It is water-soluble, yielding a red colloidal solution, and was formerly used in the textile industry but has been largely abandoned due to its carcinogenic properties. It is still used as a histological stain and as a pH indicator.

Also known as Congo Red, Cotton Red, Disodium 3,3'-[[1,1'-biphenyl]-4,4'-diylbis(azo)]bis(4-aminonaphthalene-1-sulphonate)
INCI name Direct Red 28
CAS number 573-58-0
EC number 209-358-4
CI number CI 22120
CosIng ID 30013
Last reviewed 15 July 2026

An ingredient is considered vegetarian if it avoids components derived from killing an animal.

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