Tonka bean is sold as an herb but has been banned from being put in food in the US. The main reason is that high quantities of this bean can be very toxic and taxing on the liver. The natural occuring toxin in tonka bean is coumarin. What is so amazing about couramin is that it is a potent anticoagulant. So people with thickened blood can benefit from the increased blood circulation. This goes to show that small amounts of natural toxins can actually be medicinal. Also one would have to consume quite a but of tonka to actually be harmed from it. I have to warn you that if you are taking any blood thinner medications DO NOT take tonka bean! If you do and cut yourself in the process then your're blood with flow like a river ;) This is a exlir I created which uses tonka bean and milk thistle. Milk thistle is known as one the most potent liver cleansers, so it will flush out excess courmin if needed. Well here it is.