As early as 1900, the instruction to the heads of clinics, polyclinics and other hospitals issued by the Minister of Spiritual, Educational and Medical Affairs stated that medical experiments on humans were only permissible if the persons concerned had given their consent to participate and this declaration had been preceded by proper instruction on the possible adverse consequences of the intervention. Since then, informed consent has been a fundamental principle of research ethics. However, individual aspects of this basic principle continue to be debated, such as the question of which conditions a person must fulfil in order to be able to give informed consent or which actions a person can and cannot consent to. For the historical development and theoretical foundation of informed consent, see Faden / Beauchamp 1986.