Intravenous (as a method of parenteral) alimentation becomes important whenever the nutritional needs of the body cannot be met by oral feeding; it becomes essential when death threatens because of nutritional deficiencies which can be remedied in no other way. These nutritional needs comprise six elements: water, salts, carbohydrate, protein, fat and vitamins. As far as water, salts and carbohydrate are concerned, intravenous alimentation is now a commonplace and extensively used procedure. For example, at the Barnes Hospital 125 liters and at the St. Louis City Hospital 200 liters of saline and dextrose solutions for subcutaneous and intravenous administration are used daily. Why have the remaining three nutritional elements been overlooked? If carbohydrate is important, why not protein, fat and vitamins? The answer lies partly in lack of information on the real needs for protein, fat and vitamins in patients more or less completely, though temporarily, unable to ingest any