The plasma and saliva cations in parotid malignant tumors of stages II-III were studied in 31 patients before surgical therapy and in 27 control group volunteers. The magnesium (t-Mg), calcium (t-Ca), copper (t-Cu) and zinc (t-Zn) concentrations in plasma were determined, and t-Mg and t-Ca in saliva. Our results showed that salivary and plasma t-Mg concentrations were significantly higher in patients with parotid malignant tumors in comparison to control group (saliva: 0.25 +/- 0.04 mmol/L versus 0.14 +/- 0.03/L, p < 0.01; plasma: 1.05 +/- 0.06 mmol/L versus 0.86 +/- 0.05 mmol/L, p < 0.05). The t-Ca plasma concentrations were lower for patients with parotid malignant tumors by 20-22% in comparison to the control group (p < 0.05). Plasma and salivary t-Mg/t-Ca molar ratios are respectively 0.38 and 0.12 for control group, and respectively 0.61 and 0.31 for patients with parotid gland tumors. The t-Zn plasma concentration for patients with parotid malignant tumors (0.017 +/- 0.010 mmol/L) was significantly lower (p < 0.05) in comparison to control group (0.024 +/- 0.011 mmol/L). Plasma t-Cu/t-Zn molar ratio is respectively 0.68 for control group and 1.12 for patients with parotid gland tumors. The mechanism responsible for the increase of salivary magnesium as a consequence of the development of tumoral tissue needs to be clarified.