Schmorl's Stain
for Reducing Substances

Nuclear fast red

Schmorl's solution
Ferric chloride, 1% aqueous, fresh 30 mL
Potassium ferricyanide, 1% aqueous, fresh 4 mL
Distilled water 6 mL
This solution should be freshly prepared immediately before use.

Tissue sample
5µ paraffin sections of neutral buffered formalin fixed tissue are suitable. Other fixatives are likely to be satisfactory.


  1. Bring sections to distilled water via xylene and ethanol.
  2. Place into freshly made Schmorl's solution for 10 minutes.
  3. Wash well with water.
  4. Counterstain with nuclear fast red.
  5. Rinse well with water.
  6. Dehydrate with ethanol, clear with xylene and mount with a resinous medium.

Expected results


  1. Reducing substances which may be present are coloured blue. This includes melanin, for which it is a useful method, enterochromaffin and lipofuscin.
  2. The Schmorl's solution is from Lillie's modification of Schmorl's ferricyanide reduction method for tissue reducing substances.



Lillie, R.D., (1954)
Histopathologic technique and practical histochemistry Ed.2
Blakiston, New York, USA.




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