Is Sirius Red 4B vegan?

Sirius Red 4B

Vegan

Sirius Red 4B, also known as Chlorantine Fast Red 5B or Direct Red 81, is a synthetic azo dye used in histological staining applications. It is listed in the Colour Index as CI 28160.

Also known as Chlorantine Fast Red 5B, Direct Red 81
CAS number 2610-11-9
CI number CI 28160
Last reviewed 3 June 2026

Sources

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