Castoreum

Castoreum is a secretion produced by the castor glands of beavers, located near the base of the tail. The material is processed for use in various applications and has a distinct musky aroma described as warm, leathery, with vanilla-like undertones. It is traditionally obtained from mature beavers and may be used in dried or prepared forms.

In perfumery, castoreum has long been valued as a base note and fixative, helping to add depth and longevity to fragrances. Its scent contributions can be described as animalic, resinous, and sweetly vanilla-like, which has made it a component in historical and niche perfumes. In contemporary formulations, real castoreum is uncommon in mass-market products, with many brands opting for synthetic substitutes that imitate its aroma or for other base notes and fixatives.

Historically, castoreum was also used as a flavoring agent in foods and medicines. Today, its use in flavoring is extremely limited because of ethical considerations, cost, and the availability of synthetic flavors such as vanillin and related compounds. In many cases, what is marketed as castoreum in older literature or niche products may be replaced entirely by synthetic ingredients or by beaver-derived extracts produced under more controlled or humane conditions.

Etymology and terminology note that the term castoreum derives from Latin castor, meaning beaver, and the substance is also referred to as castorium.