A Medical Power of Attorney gives specific instructions, prepared in advance, that are intended to direct medical care for an individual if he or she becomes unable to do so in the future. Plainly speaking, a Medical Power of Attorney is made in anticipation of a medical emergency. If you are in an accident or suffer a disease or disorder that may leave you incapable of making a sound medical decision, a Medical Power of Attorney permits you to choose in advance who will represent and enforce your interests. The person authorizing the other to act on his behalf is the "principal" and the one authorized to act is the "agent"

A Medical Power of Attorney should be given to someone whom you trust unreservedly; this is an individual who will be making decisions for you when you are incapacitated, even if you are not on life support or terminally ill. However, an agent does not have the authority to act until the principal's attending physician certifies in writing that the principal is incompetent.

A Medical Power of Attorney is not legally effective unless the principal signs a disclosure statement that he or she has read and understood the contents before signing the document. If the principal is physically unable to sign, another person may sign the document in his or her presence and at his or her directive. Two qualified witnesses, who are competent adults, must witness the procedure. At least one of them must not be related to the principal, the principal's attending physician or the attending physician's employee, entitled to a part of the principal's estate, an individual who has a claim against the principal's estate, or an officer, director, partner or business office employee of the healthcare facility.

An individual may revoke the Medical Power of Attorney by notifying either the agent or the principal's health care provider of his or her intent to revoke the document. This revocation will take place regardless of the principal's capability to make sound medical judgments. Further, if the principal executes a later Medical Power of Attorney, then all prior ones are revoked. If the principal designates his or her spouse to be the agent, a divorce revokes the Medical Power of Attorney.

An agent, acting in good faith, will not incur criminal or civil liability for a medical decision made under a Medical Power of Attorney.