AbstractA microwave modification of the Mallory phosphotungstic acid hematoxylin stain is detailed. The technique eliminates the use of lengthy toxic mercuric chloride mordanting and dezenkerization by substituting zinc chloride. Staining is carried out at low heat levels to preclude boiling and stain breakdown and results in sharp, contaminant-free, dark blue muscle striations within about 20min in paraffin and glycol methacrylate tissue sections. (The J Histotechnol17:125, 1994)