The effect of fluvastatin and fenofibrate on O2-generation by neutrophils and MDA concentration in mixed hyperlipidaemic patients with stable angina was studied. Thirty-five patients (13 men and 22 women aged 40-77 years) were randomly divided into two groups. Group I comprised 20 patients who were administered fluvastatin 40 mg once daily at bedtime for 30 days. Group II consisted of 15 patients who were administered fenofibrate 200 mg once daily at bedtime for 30 days. The control group comprised 11 clinically healthy persons, aged 21-54 years. Neutrophil O2-generation was measured using Bellavite et al. method and MDA concentrations in plasma and erythrocytes were determined by Placer et al. method. It was shown that fluvastatin had no significant effect on O2-generation while fenofibrate increased its generation. None of the examined drugs caused changes of MDA concentrations in plasma and erythrocytes.