Increases in the intracellular levels of glutathione (GSH) in cancer cells have been implicated in the development of acquired resistance to platinum antitumor agents. On the other hand, little information is available on the relationships between intracellular GSH levels in non-treated cancer cells and their response to platinum complexes. The present work investigated for possible correlations between concentrations of intracellular GSH/GSSG in 14 human cancer cell lines growing in vitro and the cell growth inhibitory activities of cisplatin, carboplatin, oxaliplatin, and d,l-trans-1,2-diaminocyclohexane-dichloro-platinum(II) (DACH-Pt). No statistically significant correlation between GSH levels and the activities of any of the four Pt-complexes could be found.