Quinine is a natural compound derived from the bark of the cinchona tree, which is native to the tropical regions of South America. The bark contains several alkaloids, with quinine being the most well-known for its medicinal properties. Historically, it has been used to treat malaria, a disease caused by parasites transmitted through mosquito bites. The extraction of quinine from cinchona bark has been a significant development in medicine. In the 19th century, it became a crucial treatment for malaria, leading to its widespread use. Today, while synthetic alternatives exist, quinine is still used in some medications and as a flavoring agent in tonic water.