Materia medica is a Latin medical term for the body of collected knowledge about the therapeutic properties of any substance used for healing (i.e., medicines). The term derives from the title of a work by the Ancient Greek physician Pedanius Dioscorides in the 1st century AD, De materia medica, 'On Medical Material' (Περὶ ὕλης ἰατρικῆς in Greek). The term materia medica was used from the period of the Roman Empire until the 20th century, but has now been generally replaced in medical education contexts by the term pharmacology.