"In archaeology, the discovery of ancient medicines is very rare, as is knowledge of their chemical composition," the researchers wrote. "The data revealed extraordinary information on the composition of the tablets and on their possible therapeutic use."

The disks were about 80 percent inorganic, with zinc making up about 75 percent of the inorganic components. Zinc compounds have been known since ancient times to serve as medicines, with the ancient Roman naturalist Pliny the Elder writing that they could help treat the eyes and skin.