Total parenteral nutrition is now available for the long term nutritional support for individuals who can no longer maintain their well-being in the usual oral manner. Many advances have been made in the technical aspect of safely deliverying hypertonic nutrient solutions into the bloodstream; however, very little is known about the long term metabolic effects of such artificial substances. It is the broad objective of the proposed research to determine the intravenous nutritional requirements capable of providing an optimum nutritional state to patients who now rely completely upon long term total parenteral alimentation. Areas to be investigated include the amount and type of calories and amino acids to be supplied and their interrelationships, the minimum requirements of trace metals and essential fatty acids and to determine the minimum daily infusion time needed to safely and effectively infuse the above daily requirements. Secondarily, it is to evaluate the safety and effectiveness of those intravenous nutrient preparations now available for parenteral infusion. Meaningful data and conclusions can be obtained by controlled studies in stable patients undergoing long term parenteral nutrition by utilizing standard accepted methods for determination of the subjects' nutritional status, i,e., nitrogen balance, serum and urine amino acid and fatty acid analyses, etc.