An agreement to do something or to allow something to happen, made with complete knowledge of all relevant facts, such as the risks involved or any available alternatives. For example, a patient may give informed consent to medical treatment only after the health care professional has disclosed all possible risks involved in accepting or rejecting the treatment. A health care provider or facility may be held responsible for an injury caused by an undisclosed risk. In another context, a person accused of committing a crime cannot give up his constitutional rights -- for example, to remain silent or to talk with an attorney -- unless and until he has been informed of those rights, usually via the well-known Miranda warnings.