755 ILCS 45/4-11
This Article applies to all health care providers and other persons in relation to all health care agencies on and after the effective date of this Article. This Article supersedes all other Illinois Acts or parts thereof existing on the effective date of this Article to the extent such other Acts are inconsistent with the terms and operation of this Article; provided, that this Article does not affect the law governing emergency health care. If the principal has a living will under the "Illinois Living Will Act", as now or hereafter amended, the living will shall not be operative so long as an agent is available who is authorized by a health care agency to deal with the subject of life-sustaining or death-delaying procedures for and on behalf of the principal.
755 ILCS 45/4-11