Toxicities of heavy metals is a burning issue and a topic of interest among the toxicologists throughout the world. Metals are always in use of man since long but in recent years the use of cadmium has increased in the form of various cadmium compounds such as cadmium compounds as stabilizers in plastic pipe industries and in the preparations of different alloys etc. Cadmium is even used in phosphate fertilizers and thus comes directly or indirectly in contact with human eatables like crops, vegetables and fruits. Once it is absorbed it affects almost all the organs and systems of human body especially blood components and kidneys. Always the chemical reactions of different chemicals are dependent on some influential factors, among these factors the effect of pH and temperature of the media in which these chemicals interact with each other are very much important. Keeping in view this fact we have evaluated the effect of cadmium nitrate tetra hydrate on GSH of human plasma and cytosolic fraction. Estimation of thiol was done by Ellman's modified method and was found that the interaction of cadmium nitrate tetra hydrate and GSH of these blood components was more at a pH and temperature, which were near to physiological pH and temperature of human body. This fact was proved as the estimated thiol concentration left after the interaction of cadmium nitrate tetra hydrate and thiol of these blood components was minimum at pH and temperature near to human blood pH and temperature. We concluded that the possible reason for depletion of GSH of these blood components was conversion of GSH into Cd(SG) (2) and/or GSSG formation.