Medical ethics is ethics in specific situations. The main aspects of its internal structure are the patient, the doctor, and all others concerned, all of whom are influenced by material and idealistic conditions. The rationale for their moral behaviour, such as moral dictates, can be oriented to different principles. Four principles prevail throughout the world at present: Autonomy, justice, beneficence, and non-maleficence. The principles of dignity, virtue and solidarity should also be taken into account. Medical ethics in relation to philosophy, theology, law, economics, and society has been a basic component of the practice of medicine as a rationale for the behaviour of doctor, patient and others concerned since its history began. With its research developments, our modern age has brought new challenges since 1900, demanding in turn many new guidelines and declarations; all this enhances the transparency of the discussion for all parties involved. The present can profit from suggestions made in the past, but we are also called upon to find appropriate answers to current questions. The modern realities of life, and and especially the progress that has been made in the natural sciences and technology, raise the question as to whether we need a new type of ethics. The patients' wellbeing and wishes remain paramount.