Antiparacelism and Trinity: Medical antitrinitarism from Thomas Erastus (1524–1583) to Ernst Soner (1572–1605). – There were close relationships between Renaissance medicine and antitrinitarianism in 16th and 17th century. Forming an important part of the radical reformation antitrinitarianism won many disciples in the Holy Roman Empire and proved its attraction for physicians. This paper centers on two public scandals in Heidelberg and Altdorf involving the reknown university professors and physicians Thomas Erastus and Ernst Soner. Michael Servetus' new concept of the blood (...) flow through the lungs was discussed in Heidelberg. In Altdorf Caspar Hofmann, Soner's colleague, developed a special theory of the blood flow and corresponded with William Harvey. Erastus and Soner sharply critisized the hermectical and neoplatonical ideas of Paracelsus. Although sympathizing with antitrinitarianism they denounced the Paracelsians as heretics. The Polish antitrinitarians were called Socinians, from Faustus Socinus. Their doctrine tended to be Aristotelic and rationalistic. Soner combined a socinian theology with a heterodox Aristotelianism referring to Andrea Cesalpino. Again after Soner's death some of his pupils and other physicians advocated socinianism in Gdansk (Martin Ruar, Florian Krause, Daniel Zwicker,Valentin Baumgart). (shrink)