We have treated human neuroblastoma cells with various complexes of aluminium, over a range of concentrations, and have measured the amount of aluminium entering the cells after one week, using atomic absorption spectroscopy. We have found that the cells incorporate much higher levels of the element after treatment with aluminium-EDTA than with aluminium-citrate or aluminium-maltol. With aluminium-EDTA, initially the uptake increases with increasing concentration in the medium but eventually reaches a plateau; the concentration within the cells is then higher than that in the medium. No obvious change in morphology of the cells occurs after treatment. The number of cells present after a week's treatment with aluminium-EDTA is lower than that of untreated cells but does not vary over a wide range of aluminium concentrations.