DNA lesion induced by xenobiotics is implemented either through direct interaction of the chemical with DNA through covalent binding or intercalation, or indirectly, through interference with the processes of DNA replication and repair, interaction with proteins, nuclease release from lysosomes etc. The present study emphasizes that the assessment of genotoxic risk arising from xenogenous substances demands the development of sensitive, direct and more exact genotoxic testing methods. One of them is micronucleus assay. It is a simple and quick test for investigating of cytogenic damage with the advantage that exposure to both clastogens and aneugens may be detected.