The cytotoxicity of the (CuSO4)18@DAB-dendr-(Pyrr)64 and (ZnCl2)22@DAB-dendr-(Pyrr)64 dendrimer was evaluated using three human tumor cell lines (derived from breast cancer: MCF7, cervical cancer: HeLa and acute monocytic leukemia: THP1) and one non-cancer line (immortalized human microvascular endothelial cells: HMEC1). Dendrimer modification with copper increased its cytotoxicity, almost to the level of the unmodified PAMAM dendrimer and was comparable for copper sensitive (THP1, HeLa) and insensitive (MCF7, HMEC1) cell lines (Figure1/Table1). Unfortunately, also no selective toxicity was observed for any of the chosen cells. CuSO4 and ZnCl2 turned out to be non-toxic in the tested concentration range: zinc for all four tested cell lines and copper for the MCF7 and HMEC1 cell lines.