A durable power of attorney for health care—also known as a medical power of attorney—is a legal document that a person (the principal, grantor, or donor) signs to appoint another person as the principal’s agent, attorney-in-fact, health care surrogate, or health care proxy—with authority to make health care decisions for the principal if the principal becomes physically or mentally disabled or incapacitated (incompetent) from a stroke, Alzheimer’s disease, automobile accident, or other cause.

A person appointed as agent or attorney-in-fact for health care decisions will be able to accept or refuse medical treatment for the principal, access the principal’s medical records, and in the event of the principal’s death, authorize an autopsy, donate the principal’s organs, and dispose of the principal’s body by burial or cremation.

But an agent or attorney-in-fact for health care decisions has no ability to make these decisions for the principal until the principal becomes physically or mentally disabled or incapacitated (incompetent)—unless the document provides otherwise.

A principal generally has the ability to revoke or change a durable power of attorney for health care or Advance Health Care Directive at any time before becoming incapacitated. And a principal can limit the scope of the durable power of attorney for health care or Advance Health Care Directive to limit the agent's or attorney-in-fact's powers and ability to make certain health care decisions.

In addition to these limitations, some states prohibit certain health care decisions from being made by an agent or attorney-in-fact—such as euthanasia, psychosurgery, sterilization, abortion, convulsive treatment, or placement in a mental health treatment facility.

Laws and terminology for documents related to health care decisions vary from state to state. These laws are generally located in a state’s statutes—often in the probate code or estates code.

In New York, a Durable Power of Attorney for Health Care, also known as a Health Care Proxy, is a legal instrument that allows an individual (the principal) to designate another person (the agent or health care proxy) to make health care decisions on their behalf if they become unable to do so due to incapacity. The agent can make decisions regarding medical treatment, access medical records, and handle matters related to the principal's remains after death. However, the agent's authority is activated only when the principal is deemed incapacitated, unless the document specifies otherwise. The principal retains the right to revoke or amend the Health Care Proxy at any time before they become incapacitated and can also set limitations on the agent's powers. New York law prohibits agents from making decisions about certain health care actions, such as euthanasia. The relevant statutes for these directives in New York can be found in the state's Public Health Law, specifically Article 29-C, which governs Health Care Agents and Proxies.