castorium

Castorium, commonly called castoreum, is a secretion produced by the castor glands of beavers. The glands are located near the base of the tail in beavers of the species Castor fiber (European beaver) and Castor canadensis (North American beaver). The dried and cured secretions are collected, processed, and can be used as a paste or tincture. Historically, castorium was prized in perfumery for its rich, multifaceted odor, described as leathery and animalic with sweet, vanilla-like undertones, and for its ability to act as a fixative that slows the evaporation of other fragrance notes. It has also appeared in traditional medicine and as a flavoring agent in some cuisines and medicinal preparations.

In modern perfumery, natural castorium is rare and expensive, and many houses rely on synthetic substitutes or aroma accords designed to emulate its base-note character while avoiding animal-derived materials. In flavors, genuine castoreum was used in some old recipes, but ethical, supply, and regulatory concerns have led to its near-total replacement by synthetic flavors or plant-derived alternatives. Regulatory treatment varies by jurisdiction; when used, it is typically listed as a natural flavoring or fragrance ingredient, and producers may indicate animal-derived materials in compliance with labeling laws.

Safety and ethics: Castorium is not considered acutely toxic, but as with other fragrance ingredients, it can cause allergic reactions in sensitive individuals. The use of animal-derived ingredients has prompted welfare debates, contributing to its decline in contemporary products.