The action of the food dyes E160e (20% beta-apo-8'-carotinale in oily suspension) and E160e (20% beta-carotene in oily suspension) on the clastogenic effects of the indirect alkylating mutagen cyclophosphamide (CP) and the prooxidative mutagen dioxidine (D) was examined by the using the chromosomal aberrations tests on the bone marrow cells from C57B1/6 mice. E160e in a dose of 50 mg/kg caused a significant decrease in the count of aberrant cells damaged by D or CP. When given in a dose 5 mg/kg, the dye reduced the effects of these mutagens only during preadministration. Moreover, E160e in a dose of 0.5 mg/kg substantially lowered the clastogenic effect of D after its 5-day use in combination with the mutagen E160a. Pretreatment of the animals with E160a in doses of 5 und 50 mg/kg caused a significant reduction in the cytogenetic effect of D. When used in combination with the mutagens, this dye in doses of 5 and 50 mg/kg reduced the clastogenic action of CP, when given in doses of 0.5, 5, and 50 mg/kg, it decreased the count of cells damaged by D. In other variants of the experiment E160a was inactive.