Disclosed is a configurational stereoisomer, named enantiomer E1, of bromadiolone having, by chromatographic analysis of bromadiolone including four configurational stereoisomers of bromadiolone performed under the conditions described below, a retention time t1 having a value such that t1<；t2<；t3<；t4； t2, t3 and t4 being the retention times of the configurational stereoisomers of bromadiolone different from the enantiomer E1, the analysis being performed at a temperature of 27.3° C.
