Natural product to modern discovery of their active ingredients and eventually to the development of new drugs. A large number of currently prescribed drugs have been either directly derived from or inspired by natural products. A few representative examples are listed below. Some of the oldest natural product based drugs are analgesics. The bark of the willow tree has been known from antiquity to have pain relieving properties. This is due to presence of the natural product salicin which in turn may be hydrolyzed into salicylic acid. A synthetic derivative acetylsalicylic acid better known as aspirin is a widely used pain reliever.
Hippocrates 129 to AD 200. Galen perpetuated Hippocratic medicine, moving both forward and backward. In the Middle Ages, the Islamic world adopted Hippocratic methods and developed new medical technologies. After the European Renaissance, Hippocratic methods were revived in western Europe and even further expanded in the 19th century. Notable among those who employed Hippocrates' rigorous clinical techniques were Thomas Sydenham, William Heberden, Jean-Martin Charcot and William Osler. Henri Huchard, a French physician, said that these revivals make up "the whole history of internal medicine." According to Aristotle's testimony, Hippocrates was known as "The Great Hippocrates". Concerning his disposition, Hippocrates was first