Hematoxylin is a naturally occurring stain extracted from the logwood tree. For use in staining, the hematoxylin is oxidized to hematein which combines with the trivalent mordant and is the active staining ingredient. The usual mordants for cytology are aluminum salts. Mayer’s hematoxylin is a solution of aluminum ammonium sulfate, acetic acid and hematoxylin in water. Our modified Mayer’s is intended used in our congo red stain kit, our mucicarmine stain kit and our PAS stain kit. These items are manufactured in the United States by Medical Chemical Corp.