AEC is a widely used chromogen for immunohistochemical procedures. In the past, AEC chromogens required a water-soluble mounting media because it was soluble in organic solvents. Romulin AEC from Biocare produces a reddish-orange stain. However, it is not soluble in alcohol or xylene-and can be coverslipped just like DAB. It does not fade with permanent mounting media such as PermountTM. When in the presence of a peroxidase enzyme, Romulin AEC produces a reddish-orange stain. This product comes in a 4-component system consisting of ready-to-use buffer, stabilizer, chromogen and hydrogen peroxide.