Disclosed is a dextrorotatory enantiomer of the configurational stereoisomer of difethialone, named homo-stereoisomer, the formula of which is 3-(4′-bromobiphenyl-4-yl)-1-(4-hydroxythiocoumarin-3-yl)-1,2,3,4-tetrahydronaphthalene, in which carbons 1 and 3 of the 1,2,3,4-tetrahydronaphthalene group of the homo-stereoisomer have the same absolute configuration.