early 15c., medicacioun, "medical treatment of a disease or wound," from Old French médication and directly from Latin medicationem (nominative medicatio) "healing, cure," noun of action from past-participle stem of medicare, medicari "to medicate, heal, cure" (poetic and Late Latin) from medicus "physician; healing" (from PIE root *med- "take appropriate measures"). Meaning "a medicinal substance or product" is by 1942.
