As knowledge of the biological importance of the essential trace elements has been increased and recently analytical methods for their assay have been improved and become widely available, consequently clinical interest in the subject grown. The health of human beings depends largely on a normal supply of essential trace elements and changes in trace element concentration in body tissues may lead to severe reactions. Thus it is obvious that lack of essential elements as cofactors of enzymes may have serious consequences for the orderly chain of enzyme reactions in metabolism and may lead to physiological disorders. Deficiency of essential trace elements produce multiple and diverse clinical signs and symptoms. These may arise from inadequate dietary intake, decreased bioavailability, certain disease states in which decreased absorption, excessive excretion and/ or utilization occurs. To evaluate the different physiological states in which trace element requirements are increased. To evaluate the role of essential and toxic metals in different health problems, it is necessary to determine the elemental composition of the biological samples of healthy human subjects and changes observed in elemental composition in different diseases.