Carbohydrate, fat, and amino acid metabolism from the parenteral point of view are surveyed and reviewed. Differences between the habits in the United States and Europe is stressed. It is proposed that carbohydrates other than glucose can be used; especially fat emulsions as the source of both energy and essential fatty acids for the body. Variable compositions of amino acids for different conditions as well as for adults and infants are suggested. There is also a trend to include all vitamins and minerals.In order to provide optimal nutritional effects with intravenous alimentation it is important to: 1) supply an adequate amount of amino acids; 2) supply adequate energy; 3) include at least 100 g of carbohydrate; and 4) supply adequate amounts of other nutrients (vitamins, minerals, and essential fatty acids).