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Alkaloid found in the bark of cinchona trees and shrubs. The chemical structure of this heterocyclic compound is large and complex, with several rings. For the 300 years preceding the 1940s, when newer antimalarials were developed, quinine was the only drug known to Western medicine for the prevention and treatment of malaria. The first chemical compound ever used successfully against an infectious disease, it has benefited more people than any other such drug in history and is still used to treat malaria, often in combination with other drugs. Quinine is also a flavouring agent in some carbonated beverages, including tonic water.
This entry comes from Encyclopædia Britannica Concise. For the full entry on quinine, visit Britannica.com.