Found in the bark of the cinchona tree, quinine is a compound with many medicinal applications, including fever-reducing, painkilling and anti-inflammatory properties. It was the first treatment for malaria and is still used today to treat some cases of the disease, which is caused by the parasite Plasmodium falciparum.
Several stories tell of the discovery of quinine's medicinal qualities. One legend describes a South American Indian who, while suffering from malaria, drank from a pool of bitter-tasting water contaminated by nearby cinchona trees, after which his fever disappeared. The first documented use of quinine to treat malaria occurred in Peru in 1630.
While approved by the FDA to treat malaria, quinine is not approved for its off-label use in treating nighttime leg cramps. In 2010, the FDA announced that it had received 38 reports over a three-year period of serious side effects resulting from quinine use, including blood disorders and two deaths.
A more mundane use of quinine is as an ingredient in tonic water. You might wonder if drinking enough tonic water could cure malaria. It would take a lot! A 12-oz bottle of tonic water contains 40 mg of quinine, while the daily dose to treat malaria is 700 mg to 1,050 mg per day.