Abstract: A heat-stable plasma protein solution showing no blood pressure-depressing action is obtained by adding distilled water to a paste IV-1, a waste fraction obtained from the Cohn's cold ethanol plasma fractionation method and has heretofore been discarded as a waste, to extract water-soluble proteins in the paste, heat-treating the extract at pH 4.5 to 5.5 at 50.degree. to 65.degree. C. in the presence of an organic acid to remove as precipitates lipo- and glyco-proteins contained in the extract, adding Rivanol to the resulting supernatant to remove by precipitation residual lipo-proteins giving turbidity to the supernatant, and then removing blood pressure-depressing substances present in the resulting supernatant by adsorption with an inorganic adsorbent or cation exchanger. The thus obtained heat-stable plasma protein solution shows prominent effects in the therapy of shock by acute bleeding, burns, supply of protein nutrients, hypoproteinemia, etc., and is useful for medical treatments.