Castoreum is the name perfumers give to a chemically complex glandular secretion of the castor sacs of the mature male beaver, both the European Castor fiber or the North American C. canadensis. Today, it's used in trapping, as a tincture in some perfumes, or touted as an aphrodisiac. Although modern medical use of castoreum is rare, the dried pair of scent glands (the "castors") may still be worth more than a beaver pelt itself. Castoreum appeared in the materia medica until the 1700s, used to… (More on Castoreum)