A living will—also known as an Advance Health Care Directive—is a document in which the declarant or principal (person making the living will) specifies what kind of medical treatment the declarant does and does not want if the declarant has a medical emergency and is unable to communicate those wishes. A living will may direct health care providers to administer, withhold, or withdraw life-sustaining treatments if the declarant is in a terminal or irreversible condition.

Laws and terminology for documents related to living wills, Advance Health Care Directives, Do Not Resuscitate orders (DNRs), and other health care documents vary from state to state. These laws are generally located in a state’s statutes—often in the probate code or estates code.

In Illinois, a living will is recognized under the Illinois Living Will Act (755 ILCS 35/). This document allows an individual, known as the declarant, to express their wishes regarding medical treatment in the event they are unable to communicate due to a terminal condition. The living will can specify whether the declarant wants life-sustaining treatments to be administered, withheld, or withdrawn if they are diagnosed with a terminal condition and are unable to make decisions for themselves. It is important to note that the living will only takes effect when the individual is terminally ill and does not cover other medical situations. Additionally, Illinois recognizes other advance directives such as the Power of Attorney for Health Care, which allows an individual to appoint an agent to make health care decisions on their behalf if they are unable to do so. Do Not Resuscitate (DNR) orders are also used in Illinois to indicate that a person does not want resuscitation if their breathing or heartbeat stops. These documents should be discussed with an attorney to ensure they meet the individual's needs and comply with Illinois law.