In chronological order, and in the light of bioethics principles, the authors describe the Italian regulation which concerns the protection of human subjects participating in clinical trials from 1990 to July 2004, the related institution of Ethical Committees and the adoption of the tool of the informed consent. The publication includes the ties that have connected the Italian regulations to the European one since the beginning. During such period, the reception of the Good Clinical Practice guidelines - which occurred in 1992 first, and finally in 1997 - has led to the establishment and the fostering of such important institutions as well as to the shaping of a network of Ethical Committees working on clinical trials and coordinated at a central level. In this paper the authors examine in particular: clinical trials of medicinal products, of medical devices and of ionizing radiations. Some implications of ethics are also discussed.