Cinchona is a tree. People use the bark to make medicine. Cinchona is used for increasing appetite; promoting the release of digestive juices; and treating bloating, fullness, and other stomach problems. It is also used for blood vessel disorders including hemorrhoids, varicose veins, and leg cramps.
It's also known as Jesuit's Bark, Peruvian Bark, Quina, Quinine Bark, and Red Cinchona. Cinchona bark is most commonly used for the production of quinine, both for medicinal purposes and for flavoring of tonic water.