Alcian yellow

Alcian yellow is an azo dye with the formula 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