Pre- and peroperative blood saving can be realised in different ways, without inducing important changes in the biological parameters of the organism. Different replacement solutions are studied in detail. Three principal techniques are as follows: a) The peroperative autotransfusion consists in recovering the blood lost in the operative field during the surgical intervention, filtering it and transfusing it at the end of surgery. b) The peroperative normodilution consists in collecting a certain amount of blood (till up 2 l.) from the patients before operation; it is replaced by plasma expanders and transfused at the end of operation. c) The third technique, called the 'frog leap', consists in collecting blood during the weeks preceding surgery, in various amounts in function of the importance of the estimated blood loss. This blood is stored and transfused during intervention.