Coumarin is a phytochemical with a vanilla like flavour. Coumarin is found in several plants, including beans, lavender, liquorice, strawberries, apricots, cherries, cinnamon, and sweet clover. Coumarin is responsible for the sweet smell of new mown hay.

Coumarin can occur either free or combined with the sugar glucose (coumarin glycoside).

It is often used as an aroma component in artificial aromas.