Iatrochemistry (; also known as chemiatria or chemical medicine) is a branch of both chemistry and medicine. Having its roots in alchemy, iatrochemistry seeks to provide chemical solutions to diseases and medical ailments. This area of science has fallen out of use in Europe since the rise of modern establishment medicine. However, iatrochemistry was popular between 1525 and 1660, especially in the Low Countries. Its most notable leader was Paracelsus, an important Swiss alchemist of the 16th century. Iatrochemists believed that physical health was dependent on a specific balance of bodily fluids. Iatrochemical therapies and concepts are still in wide use in South Asia, East Asia and amongst their diasporic communities worldwide. History in Europe The preparation of medicines had become a part of alchemy by the early modern period. Around 1350, John of Rupescissa advocated the extraction of the "essence" of both plants and minerals. He often used two relatively new substances during this period: an alcohol distilled from wine and strong mineral acids. Later, "Pseudo-Llull" (i.e. the body of work attributed to, but not necessarily written by, Ramon Llull) picked up and helped in expanding John of Rupescissa's theory. The most effective and vocal proponent of iatrochemistry was Theophrastus von Hohenheim, also known as Paracelsus (1493–1541). He put his effort into the transmutation of metals and emphasized iatrochemistry in his works. Paracelsus believed that diseases were caused by poisons, but that poisons were not entirely negative. He suggested that poisons, or diseases, could also be cured by poisons; thus, poisons could have beneficial medical effects. Paracelsus's claim led to many chemically prepared medicines in this period which contained toxic components: arsenic, antimony, mercury, lead, and other heavy metals. However, his views were not accepted by many scholars until his writings were organized into systematic form by his followers. Gradually, many physicians accepted Paracelsian remedies, although some disagreed with Paracelsus's philosophy. Philipp Ulstad, who wrote some of the first books on chemical medicine, paved the way for a closer link between alchemy and medicine. His lucid, concise prose made Coelum philosophorum (1527) one of the most reissued chemical-medicine books of the 16th and 17th centuries. This documentation of knowledge was a trend that began in the mid-16th century and it allowed knowledge that was typically limited to those in apprenticeships to be accessible to anyone. In 1609, Flemish chemist Jan Baptista van Helmont began a seven-year period of individual