[Confidentiality and informed consent. A necessary reflection]

This article analyzes a patient's rights to confidentiality, to be informed, to be able to freely exercise his/her choice, and to opt to not have an investigation or experiment carried out on his/her body. This article deals in depth with the confidentiality issue in health care, reviewing the roles of the patient and the health care professional. Finally, this article presents a detailed analysis about informed consent, tracing its legal origins and development, the ethical principles which should compose it, the proper way to present information about it, etc.