Disclosed is a composition including flocoumafen and an amount of a configurational stereoisomer of flocoumafen, named enantiomer E4, such that the ratio of this amount to the amount of flocoumafen in the composition is less than 10%, the enantiomer E4 being present with the exclusion of a racemic mixture, the enantiomer E4 having, by chromatographic analysis of flocoumafen, a retention time t4 having a value such that t1