Athelas

From Protectors of the Plot Continuum

Athelas, also known as Kingsfoil, is a plant from Middle-Earth and the Lord of the Rings continuum that has minor curative properties which are much stronger when used by a king.

It also acts as a cure for the Black Breath.

Due to the actions of PPC Bioengineering Inc, athelas has become a "secret ingredient" in many Real World medicines.