The concept of care risk includes any undesirable situation, or any factor contributing to its occurrence, related to the health care received and which might have negative consequences. It includes conditions like adverse effects of medicines, negligence and litigation. A safe clinical practice requires that three objectives be obtained: to identify which diagnostic and therapeutic clinical procedures are the safest and most efficient; to assure that they are applied to those who need them; and to carry them out correctly and without mistakes. In this sense, what are needed, on the one hand, are systems of notification and epidemiological studies, and, on the other, actions at different levels of the health system. The maximum safety of the patient is obtained by a suitable knowledge of the risks, elimination of those that are unnecessary, and prevention and protection in those that must inevitably be assumed. This is because safety is not the same thing as absence of risk.