The clastrogenicity of seven anthraquinones was investigated in a V79 Chinese hamster cell line expressing only the reductive pathway enzymes and in three derived cell lines transfected and expressing three rat cytochrome P450 (1A1, 1A2, 2B1). The result have shown that chromosomal aberrations are modulated in similar manner both in parenal and transfected V79 cell lines, suggesting that the clastogenicity of these compounds is not mediated by cytochrome P450 dependent monooxygenases.