title: Janus Green B
text: # Janus Green B
  
  Janus Green B is a basic dye and vital stain used in histology. It is also used to stain mitochondria supravitally, as was introduced by Leonor Michaelis in 1900.
  
  The indicator Janus Green B changes colour according to the amount of oxygen present. When oxygen is present, the indicator oxidizes to a blue colour. In the absence of oxygen, the indicator is reduced and changes to a pink colour.
  
  