<unk>  (INN) or<unk>  (USAN) is a naturally occurring anticoagulant drug that depletes stores of vitamin K (similar to warfarin, a drug that<unk>  inspired). It is also used in biochemical experiments as an inhibitor of reductases.<unk>  is a natural chemical substance of combined plant and fungal origin. It is a derivative of coumarin, a bitter-tasting but sweet-smelling substance made by plants that does not itself affect coagulation, but which is (classically) transformed in mouldy feeds or silages by a number of species of fungi, into active<unk> .<unk>  does affect coagulation, and was discovered in mouldy wet sweet-clover hay, as the cause of a naturally occurring bleeding disease in cattle. See warfarin for a more detailed discovery history. Identified in 1940,<unk>  became the prototype of the 4-hydroxycoumarin anticoagulant drug class.<unk>  itself, for a short time, was employed as a medicinal anticoagulant drug, but since the mid-1950s has been replaced by its simpler derivative warfarin, and other 4-hydroxycoumarin drugs. It is given orally, and it acts within two days.
Dicoumarol
Triphenylbromoethylene
Tetrachlorodecaoxide
Methylphosphonyl difluoride
Tetraethyllead
Selenium disulfide
Phenylsilatrane
Chlorotrianisene