Selling tonka beans to eat has been illegal in the US since 1954. Foods containing tonka are considered to be 'adulterated', though that hasn't stopped them appearing on the menus of Michelin-starred restaurants, from New York to California. In fact, the United States is the biggest importer of tonka on the planet.

Why are tonka beans illegal?

Stateside, that was about to change, as the feds made it known that the naturally occurring compound coumarin (which causes liver damage in lab animals) was present in unacceptable levels in tonka, and so the beans were banned. ...

Is tonka bean toxic?

Tonka beans contain a chemical compound, coumarin which is toxic when consumed in high quantities. Coumarin is the same chemical that's responsible for the fruity-sweet scent of the tonka seeds. The Food and Drug Administration FDA banned coumarin-containing foods back in 1954.