Paracelsianism (also Paracelsism; German: Paracelsismus) was an early modern medical movement based on the theories and therapies of Paracelsus. It developed in the second half of the 16th century, during the decades following Paracelsus' death in 1541, and it flourished during the first half of the 17th century, representing one of the most comprehensive alternatives to learned medicine, the traditional system of therapeutics derived from Galenic physiology.

Based on the by then antiquated principle of maintaining harmony between the microcosm and macrocosm, Paracelsianism fell rapidly into decline in the later 17th century, but left its mark on medical practices. It was responsible for the widespread introduction of mineral therapies and several other iatrochemical techniques.