Alcian yellow

Alcian yellow is an azo dye with the formula (CH3[(CH3N)2CS]2C6H2SNCC6H4)2N2. Its structure consists of a largely conjugated array of benzene, benzothiazole and isothiouronium units.

Histological Use
Alcian yellow is used in histology in conjunction with toluidine blue to help visualize H. pylori. The resulting structures are stained as follows:

– Mucin: yellow

– H. pylori: blue

– Other cellular components/background: shades of blue