Malachite green

Is acid base indicator: in aqueous solutions in the silnokisly environment has yellow coloring, at rn 0,1-2,0 coloring pass in blue-green, in the silnoshchelochny environment at rn higher than 11,6-13,6 becomes colourless because of accession of hydroxyl with formation of triphenyl carbinol.

application

in microscopy for vital staining of cellular kernels;
for coloring of erythrocytes, eggs of ascarids;
as medicine in veterinary science — in particular, at treatment of aquarian fishes for infectious diseases.
Earlier it was applied to coloring of Estragon soft drink. Now it is not applied in connection with suspicions on carcinogenicity.