Is Direct Red 28 vegetarian?
Direct Red 28
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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