The amino acids of hydrolyzed protein have been shown in previous studies1 from this laboratory and clinic to be effective in promoting the synthesis of serum albumin and in various types of hypoproteinemia. Nearly all of these were instances of chronic or subacute hypoproteinemia, many of nutritional origin. In this preliminary report we present experimental evidence that the same mixture of amino acids and polypeptides is beneficial in the therapy of acute protein loss which occurs in severe uncompensated (i. e. fatal) hemorrhage. Although the value of plasma and whole blood transfusions is an established principle of vast importance in the treatment of shock, it is probable that in wartime the number requiring such treatment might well exceed the available supplies of plasma and that in the armed forces many situations might arise in which blood donors were not available. Because of the relative ease and economy with which