Several methodologies have been proposed in order to establish anticancer action, mainly focused onin vitro cytotoxicity valuation on neoplasic cell lines derived from human cancer. However, most ofthese cell lines are metabolically incompetent, restricting model sensibility and generating false negativeanswers. Hep-G2 cell line is widely used because of its high sensibility reflecting phase I and II activityof some enzymes of phase I and II, which play an important role in activation and detoxification ofxenobiotics. In this study, Hep-G2 is used as a model to find cytotoxic activity produced by 2-amino- 1-methyl-6-phenylimidazo [4,5-b]pyridine (PhIP) and Cyclophosphamide, in presence or absence ofinductor agents. This analysis was carried out by measuring indirectly viable number of cells with assayslike MTT and resazurine staining. In addition, the possibility of co-cultures with other cell lines wasevaluated according to strengthen method sensibility. Cytotoxicity of PhIP and cyclophosphamide wasobserved with the cellular staining methods. For this reason a co-culture system was established. Theanswer was similar to independent cell lines. These results propose that pre-treated Hep-G2 cells withsome inductive agents show sensibility by PhIP as different authors postulate.