The tonka bean, which gives off notes of vanilla, cherry, and almond, infuses desserts, drinks, and even perfumes around the world. British chefs mix it into cocktail syrups and grate its shavings over pastries, while pâtissiers in France whip up tonka bean–infused ice creams and custards. In fact, the French love the bean so much, they’ve dubbed their obsession fièvre tonka, or “tonka fever” (a play on fève, the French word for “bean”).

And yet, if you’re in the United States, stocking these wrinkled, raisin-looking beans in your spice cabinet could get you raided by the Food and Drug Administration. Tonka beans, a product of the South American cumaru tree, contain a naturally occurring chemical known as coumarin. Since coumarin can cause health problems such as liver damage, the FDA has enforced a ban on tonka beans since 1954.

However, it would take eating 30 whole tonka beans to experience any negative effects from this toxicity. And no one eats the beans whole. Due to tonka’s potent flavor profile, a sprinkle of its shavings is enough to create a rich and heady aroma. By some reports, a single bean can flavor as many as 80 dishes.

The low levels of coumarin, coupled with the fact that the chemical appears in many other legal ingredients (such as lavender and cinnamon), has led many American chefs to ignore the ban. In 2006, the FDA raided Chicago restaurant Alinea after hearing that chef Grant Achatz used the beans. It mustn’t have been too discouraging: Two years later, Achatz’s Alinea cookbook featured a recipe for tonka bean sponge cake.