ChEBI: (S)-warfarin sodium is an organic sodium salt having 2-oxo-3-[(1S)-3-oxo-1-phenylbutyl]-2H-1-benzopyran-4-olate as the counterion (the racemate is warfarin sodium, an anticoagulant drug and rodenticide). It contains a (S)-warfarin(1-). It is an enantiomer of a (R)-warfarin sodium.