Metals are cytotoxic and could be harmful to human health; however, as their effects are dose dependant, some of them could be used in chemotherapy. In the present work, mineral chromium (VI) showed that it is cytotoxic on both tumour (MCF-7, HeLa, Hep2 and Caco-2) and non-tumour (HEK293) cell lines. Interestingly, among seven complexes of arene tricarbonylchromium, chromium (0) becomes more efficient in targeting tumour cell lines with less toxicity to non-tumour cells. Three of complexes (formyl benzene tricarbonylchromium 1, anisol tricarbonylchromium 2 and trimethoxy tricarbnylchromium 3) in this study show a decrease of IC50 values for all tested tumour cells compared to the non-tumour cells HEK293. The remaining compounds have an opposite effect; they are less toxic to tumour cells compared to HEK293. The present work demonstrates that some arene tricarbonylchromium are selectively active against cancer cells by inducing apoptosis. The role of aldehyde and methoxyl groups in arene tricarbonylchromium is shown in complexes acquiring the selective tumour cytotoxicity.