The Swiss-Austrian-German surgeon-alchemist-mystic Theophrastus von Hohenheim (1493-1541)—also known as Theophrastus Bombastus Aureolus von Hohenheim, or simply Paracelsus—is best known to medical history as a lone revolutionary. Legend has him burning Avicenna's Canon of Medicine and other classical medical texts in the town square of Basel, Switzerland, in 1527. These texts elaborated on the balanced humors of Galen, while Paracelsus, a much-traveled mining physician-surgeon, promulgated a toxicological and ontological concept of disease. Diseases were poisonings. The poisons were counteracted by other chemical substances, often with their own toxic properties. Paracelsus was a proto-homeopath; often his remedies were only slightly different from the harmful substances from which they were derived.
Hamlin C. Paracelsus: Medicine, Magic and Mission at the End of Time. JAMA. 2009;301(12):1293-1294. doi:10.1001/jama.2009.395