Catechism of the Catholic Church §1512 — excerpt
From ancient times in the liturgical traditions of both East and West, we have testimonies to the practice of anointings of the sick with blessed oil.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: Council of Trent (1551) DS 1696