The option applies to patients with a prognosis of no more than six months.
Using the symbols has been “a source of pain and anguish" for American Indian tribes, said Gov. Janet Mills (D).
The measure was hailed by environmental groups, which called the products "unnecessary" and harmful to the planet.
"There is power in a name and in who we choose to honor,” Maine Gov. Janet Mills said Friday.
In her first days in office, the state's first female governor expanded Medicaid and announced plans for an opioid czar.