Abstract: Derivatives of simple carboxylic acids, particularly trisodium citrate and other citrate salts are effective agents for enhancing the production of blood clotting factors. Addition of citrate to plasma, especially at concentrations between 2 and 10% by weight, does not appreciably denature labile proteins. However, citrate is effective in inactivating or inhibiting a variety of pathogenic microorganisms. Further, the added citrate potentiates or enhances the killing of microorganisms by heat treatment. The added citrate causes a dramatic increase in the weight of cryoprecipitate that can be produced from plasma by the usual procedures. The majority of significant clotting factors are greatly concentrated in the resulting cryoprecipitate. Increasing the amount of citrate in blood bags so that the final concentration will be at least 2% by weight results in plasma that provides improved platelet concentrates because added citrate helps eliminate contaminating microorganisms.