The cytotoxic effects of cadmium and lead: non-essential trace metals in combination with important trace elements-zinc and iron respectively were studied on cell division and chromosomal aberrations in leaf-tip cells of Vallisneria spiralis L., a submerged aquatic plant. The results showed that the toxic effects of lower concentrations of heavy metal lead, with respect to the parameters mentioned, could be antagonised by the essential metal iron. Zinc, on the other hand, further accentuated the effect of cadmium: the frequency of dividing cells decreased and the percentages of chromosomal aberrations were significantly high in the combination sets.