Medicine can be dangerous for the patients, the caregivers, the visitors and the environment. Technological progress provides devices and drugs that are always more powerful, more efficacious, but at the same time able to lead to severe side effects. This paper describes the system set up in a university hospital to fulfill legal requirements. Specialists in specific fields build up commissions, which are united in a coordination office. A general policy for the hospital has been decided, but each commission is responsible for managing the risks in its field. The overall philosophy moved from a quality assurance to a quality management system, in which the employee involved in an incident or an accident is no longer considered the only culprit except in cases of obvious violation of established procedures. In order to be efficient, the system must be as simple as possible, and well known, so that collaborators gain confidence in it. Once this cultural revolution is accomplished, quality but also security of the procedures will be improved. Its impact on cost is more questionable, as the system generates running costs which might be higher than the savings it might bring.