The cell system that detoxificates organic xenobiotics comprises three stages. Each of them involves a number of enzymes that, depending on the character of the degraded organic compound, lead to its transformations. The enzymes of the first stage – bioactivation – are generally polysubstrate mono- oxygenases, flavine-containing monooxygenases (FMO), and the enzymes showing hydrolytic and oxido- reductive activity. Induction of the enzymes influenced by xenobiotic has been confirmed by the SAGE studies (Serial Analysis of Gene Expression).