The ill effects of blood transfusion could be clinically prevented by using Ravonal, Anergen or Contomin befere transfusion. In all cases who had ill effects by transfusion, the decrease of serum calcium content and the increase of serum nucleic acid content was observed. No distinct changes of the serum calcium and serum nucleic acid content were seen by the blood transfusion when the clinical ill effects did not occure.