Peroxidase chromogen-substrate 3-amino-9-ethyl-carbazole (AEC) is an excellent chromogen system that is used in Immunohistochemistry (IHC) and Immunocytochemistry (ICC). This chromogen system gives bright red color and is very compatible with hematoxylin nuclear counterstain. This chromogen is soluble in alcohol and organic solvents therefore cannot be mounted with organic mounting medium. We recommend our aqueous mounting medium ImmunoHistoMount (IHM) for mounting of this chromogen.