It is a common misconception that aspirin is found in the bark of the willow tree. A related compound called salicin does indeed occur in willow bark, thereby explaining the use of the bark as a medication since the time of Hippocrates. But salicin is very irritating to the stomach, a problem that prompted the Bayer company to look for an alternative. One of its chemists, Felix Hoffmann, synthesized acetylsalicylic acid in 1898 and found it to be a great improvement over other salicylates. A triumph of chemistry over nature!