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 Ohio, a living will is a legal document that allows an individual, known as the declarant, to outline their preferences for medical treatment in the event that they are unable to communicate their decisions due to a terminal illness or a permanently unconscious state. Ohio Revised Code Chapter 2133, also known as the 'Ohio Advance Directives Law,' governs the use of living wills and other advance directives in the state. The living will can include instructions on the use of life-sustaining treatment, including resuscitation, mechanical ventilation, and artificial nutrition and hydration. If the declarant is determined to be in a terminal condition or permanently unconscious by two physicians, the living will directives come into effect. Ohio law also recognizes Do Not Resuscitate (DNR) orders, which are separate from living wills and instruct medical personnel not to perform CPR if the patient's breathing or heart stops. It is important for individuals to discuss their wishes with their family and their attorney, and to ensure that their living will is properly executed, witnessed, and accessible to healthcare providers to ensure their wishes are followed.