Modern medicine has given doctors more and more possibilities for "manipulative" intervention in natural processes. However, even in the context of daily medical routine of beginning, continuing or terminating treatment, the doctor is repeatedly faced with the dilemma of whether to make use of the opportunities open to him. Contrary to the widely-held view that such decisions are of a purely empirico-medical nature, it becomes apparent with reference, for example, to the definition of death and the discontinuation of treatment that these decisions also have a normative-evaluative character. In relation to the postulate of the widest possible "medical discretion" emphasis is attached to the necessity for a legal framework for four functions of the law as regards the relationship between doctor and patient: protection--avoidance of abuse--presentation of guidelines--stabilisation of confidence. In conclusion the question of medical freedom in relation to active euthanasia is considered.