In September 2013, popular blogger “The Food Babe” released a video proclaiming that beavers “flavor a ton of foods at the grocery store with their little butthole!” Since then, the internet has been crowded with alarmist posts saying that beaver’s butts are used to flavor everything from soft drinks to vanilla ice cream. The culprit behind this scare is a flavorant called castoreum—but what exactly is it, and is it worth all the fuss?

What is Castoreum?

Castoreum is a substance secreted by male and female Alaskan, Canadian, and Siberian beavers from pouchlike sacs located near the base of their tails (castor is the word for beaver in Latin). Beavers can’t see or hear very well, but they have a great sense of smell—and as a result of their castoreum glands, they also smell great. They use their castoreum in part to mark their territory, secreting it on top of mounds of dirt they construct on the edges of their home turf. (The castoreum squirting out is apparently so loud, you can hear it if you’re standing nearby.) Beavers also use the fatty, waxy secretion to waterproof their fur.

An odorous combination of vanilla and raspberry with floral hints, castoreum carries information about a beaver’s health and helps to make distinctions between family members and outsiders. Beavers are so interested in the smell that historically, fur trappers would bait traps with castoreum.

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When castoreum is fresh, it’s a fluid that ranges in color from yellow and milky to grey and sticky, depending on the type of beaver and its gender. In a live animal, this fluid is milked and dried to a solid for perfume making. In a dead animal, the entire castoreum gland is removed and, traditionally, preserved by smoking it over a wood fire.

For much of its history, castoreum was used as a medicine. Roman women inhaled the fumes of castoreum burned in lamps because they believed it would induce abortions (it didn’t). Hildegard von Bingen, a 12th-century Benedictine abbess, mystic, and scholar, wrote that powdered beaver “testicles” drunk in wine would reduce a fever; the castoreum gland, when dried, is easily mistaken for testes. Castoreum has also been used to treat headaches, which makes sense given that it contains salicylic acid, the main ingredient in aspirin.

Read more: Mental Floss