The consumption of platelet products in Finland is exceptionally high. For the most part, platelets are transfused pre-operatively to thrombocytopenic patients in order to prevent hemorrhage. Most of the minor procedures could, however, be conducted even if the patients'platelet levels would be lower than usual. In cardiac surgery, platelets are used because of the hemorrhagic diathesis associated with platelet inhibitors. Platelet inhibitors will, however, also bind to transfused platelets, whereby instead of prophylactic platelet transfusions it would be more sensible to leave the thorax open and not carry out ineffective platelet transfusions until the effect of the inhibitors has run out. We outline the prophylactic use of platelets based on recent international clinical practice guidelines.