Blood autotransfusion has entered a new phase in blood transfusion technique, since it represents an important alternative in eliminating the risks connected with blood transfusion: viral hepatitis, AIDS, blood transfusion reactions, and alloimmunization. Transfusion requirements during cardiac surgical procedures have steadily decreased; nowadays most adult patients require no transfusion during surgery. Patients (pts) receiving bank-blood may develop infectious diseases (hepatitis, AIDS, etc.). We have studied how to avoid the risk of infections with homologous blood transfusions. We present our experience of day-hospital pre-operative autologous blood collection. One-hundred-eighty-nine patients undergoing primary myocardial revascularization or valvular replacement were submitted to the drainage of 350 ml of blood three times every four days before surgery. The blood was centrifuged at once, to separate red cells from plasma. Surgeries were performed 21 days after the first drainage; iron therapy was recommended. After surgery pts received blood only if haematocrit was lower than 28%. The following data were recorded: no. of pts who received homologous blood; blood loss and homologous total blood volume used for each pt. Average blood loss was 1230 cc for ischemic pts and 701 cc for valvular pts. Non-A non B hepatitis occurred in 3/189 pts (1.5%). All of them had received homologous blood transfusions. Our data show clearly that autotransfused pts had a better post-operative period; less bank-blood and fewer transfusions have been used. No pt had collateral effects such as angina or hypotension from blood drawing. Our data show that severe cardiac diseases do not represent an absolute contraindication to heavy blood drainage.(ABSTRACT TRUNCATED AT 250 WORDS)