The German transfusion laws authorize and instruct the German Medical Association to institute a working group to provide "Guidelines for Therapy with Blood Components and Plasma Derivatives" for the critical use of blood products to promote a standardized hemotherapy and to help to protect patients from avoidable risks. In particular, because the collection of such products requires the willingness of numerous volunteers to donate blood, the responsible and carefully considered application of blood products is mandatory. For the first time, the recommendations have been evaluated on evidence-based criteria and listed for many specific medical interventions so that comprehensive procedures can now be created for the transfusion personnel in hospitals and clinics.