Theriac was an ancient antidote against poisons, as well as a strong medicine for serious diseases and plagues. Theriac was a much-needed compound drug, and therefore authorities took an active part in its production. We learn from historical sources that commercial ties and networks between countries were linked with the trade in the ingredients of theriac. The vast majority of these ingredients (of plant, animal, and inorganic origin) were brought from the region of the Dead Sea and from other parts of al-Shām. During the tenth century theriac specialists were active in Jerusalem, producing the antidote and exporting it to other countries. During the Ayyubid and Mamluk periods, Egypt became the main centre of production for theriac. The uses of theriac were known and applied in the East throughout the late medieval and early modern periods right through to modern times.