Painting showing the Countess of Chinchon (right), the wife of the Spanish Viceroy to Peru (centre), receive a drink made from the bark of a tropical tree traditionally used by the native inhabitants to cure malaria. A native Peruvian (left) is holding some of the bark in his hand. The tree genus whose bark was used was named Cinchona by Linnaeus. The active ingredients, quinine and cinchonine, were first isolated by French chemists Pelletier and Caventou. Quinine was the best antimalarial drug until the 1930s and Cinchona trees became rare as they were over-exploited.