Genotoxic properties of dihydroquercetin were in vivo studied by the method of chromosome aberrations counting and DNA-comet assay. Dihydroquercetin administered repeatedly (5 times, 0.15 and 1.5 mg/kg) or once in doses of 15, 150, and 2000 mg/kg induced no DNA damages in mouse bone marrow, blood, liver, and rectal cells. Single administration of this preparation in doses of 1.5 and 150 mg/kg and 5-fold administration in a dose of 1.5 mg/kg had no effect on the level of chromosome aberrations in mouse bone marrow cells.