A rodenticidal bait composition includes bromadiolone mainly in the form of the homostereoisomer of formula 3-[3-(4′-bromo-[1,1′-biphenyl]-4-yl)-3-hydroxy-1-phenylpropyl]-4-hydroxy-2H-1-benzopyran-2-one, where carbons 1 and 3 of the 3-hydroxy-1-phenylpropyl group have the same absolute configuration. A method for controlling rodent pests using the rodenticidal bait is also described.