Castoreum
Modern use of castoreum is rare in medicine. However, the dried pair of castors may still be worth more than the beaver's fur. Castoreum appeared in medicine until the 1700s. It was used to treat many different sicknesses. Some of the sicknesses it helped treat are headache, fever, and hysteria. The Romans believed the smells made by burning castoreum could bring about an abortion. Paracelsus thought it could be used in the treatment of seizures. Medieval beekeepers used it to make more honey.