Informed consent is a prerequisite for the ethical and legal validity of the emergency intervention in emergency medicine, since it protects the fiduciary relationship between the physician and patient; the principle of honesty that grounds this relationship; the principle of autonomy that necessitates right of self-determination; and the principle of respect for persons. Informed consent in emergency medicine, which is supposed to include the nature, benefits and risks of emergency medical intervention, differentiates with respect to definite groups of patients: (1) conscious patients, (2) unconscious patients, and (3) children and mature minors. In addition, informed consent differentiates between medical, psychological and even social circumstances of the patients, referred to as valid consent, expressed-explicit consent, blanket consent, presumed consent, tacit consent, proxy consent, and parental consent. There are a few exceptions in which emergency medical intervention is administered without informed consent. In addition to the exceptions of life-saving interventions, when a patient can not decide for herself/himself, intervention of the physician in the best interest of the patient or children is based on the "therapeutic privilege" of the physician. As an ethically defensible right, since therapeutic privilege may open a door to hard paternalistic approaches, in those situations, emergency physicians should be cautious not to violate a patient's autonomy.