Iatrochemistry (from Ancient Greek ἰατρός (iatrós) 'physician, medicine'; 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.