Grocott's methenamine silver stain

In pathology, the Grocott-Gomori's (or Gömöri) methenamine silver stain, abbreviated GMS, is a popular staining method in histology.

It is used widely as a screen for fungal organisms. Particularly useful in staining carbohydrates.

It can be used to identify the yeast-like fungus Pneumocystis jiroveci which causes a form of pneumonia called Pneumocystis Pneumonia (PCP) or Pneumocystosis.

The cell walls of these organisms are outlined by the brown to black stain.