quinine

An alkaloid with the chemical formula C₂₀H₂₄N₂O₂, originally derived from cinchona bark (from plants of the genus Cinchona), used to treat malaria and as an ingredient of tonic water, which presents as a bitter colourless powder; also, a drug containing quinine or a chemical compound derived from it.

(no longer used) To treat (someone) with quinine.