There has not as yet been widespread application of the large amount of information which has been accumulating in the field of metabolism of amino acids. There are several ways in which this information could be utilized. Both the prevention and treatment of kwashiorkor might be efficiently accomplished by the supplementation of existing diets with the specific amino acids in which they are deficient. A study of the requirements and of the patterns of excretion of amino acids in various disease states might demonstrate either a qualitative or quantitative difference in requirements of amino acids produced by the pathologic state. Lastly, it is quite possible that a study of metabolism of amino acids in as yet unexplained syndromes might reveal hitherto unrecognized metabolic aberrations.