Coumarin is a chemical substance that is been extracted from many plants, in notably high concentration in woodruff (Galium odoratum, Rubiaceae). It has a sweet scent, readily recognised as the scent of newly-mown lawns. It has clinical value as the precursor for several anticoagulants, notably warfarin. It is also used as a gain medium in a type of dye laser. Coumarin is slightly poisonous and should only be consumed in small amounts, otherwise headaches or even mind-altering effects can ensue.
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