The invention relates to a configurational stereoisomer, referred to as enantiomer E1, of flocoumafen, said enantiomer E1 having, as determined by the chromatographic analysis of the flocoumafen, carried out under specific conditions, a retention time t1 with a value such that t1 < t2 < t3 < t4; t2, t3 and t4 representing the retention times of the configurational stereoisomers of flocoumafen different from said enantiomer E1, said analysis being carried out at a temperature of 23.5°C.
