Is it ensure, insure, or assure?
"to treat medicinally," 1620s, a back-formation from medication, or else from Late Latin medicatus, past participle of medicare. Related: Medicated; medicating. The earlier verb in English was simply medicin (late 14c.).
medicate med·i·cate (měd'ĭ-kāt')
v. med·i·cat·ed, med·i·cat·ing, med·i·cates
To treat by medicine.
To tincture or permeate with a medicinal substance.