2,3,5-triphenyltetrazolium chloride is an organic chloride salt having 2,3,5-triphenyltetrazolium as the counterion. It has a role as an indicator and a dye.
2,3,5-Triphenyltetrazolium chloride is a colorless water-soluble dye. In the mitochondria of living cells, it is reduced to a deep red, water-insoluble compound (formazan). 2,3,5-Triphenyltetrazolium chloride helps to distinguish between viable and infarcted brain tissue after stroke.