@SunnyDay Clove and Peru balm scented snuff might contain more or less eugenol, too. Hepatotoxic doses are rather high both for eugenol and coumarin, though (i.e. relatively low toxicity). Occassional pinch of Elmo’s won’t do much harm to you (even if you are a rare person with low CYP2A6 function), as well as infrequent Schmalzler with paraben.
Or just make safer tonka scented snuff yourself. Putting one bean into a large can of snuff for some days would result in very low-coumarine snuff, but it will be enough to change the character of snuff.
Lavender, parsley, strawberries, cherries, apricots, licorice, bergamot, camomile and many more herbs contain coumarines. Quantity is all that matters. There are lots of far more hazardous substances around us.
By the way, coumarines have some anticancer properties, too.
Interesting article on coumarines:
http://www.academia.edu/1445257/Plant\_coumarins\_myths\_and\_realities