Background: This Methylene Blue is a light blue counterstain designed for counterstaining immunohistochemistry chromogens like DAB (GTX28196). This is an alternative counterstain that can be used in place of hematoxylin. It is an excellent counterstain for use with immunogold staining. Specimens counterstained with Methylene Blue can be dehydrated and mounted with organic solvents-based plastic polymers such as Clarion (Cat. No. GTX73339, GTX73340) or Permount. This counterstain is not compatible with aqueous mounting media. Methylene Blue Counterstain is not compatible with Crystal/Mount, Gel/Mount or other aqueous mounting media.