In vivo study has been conducted on 47 healthy women and men in order to investigate whether daily intake of powdered propolis extract during 30 days has any influence on the following blood parameters: activity of superoxide dismutase, glutathione peroxidase and catalase, concentration of plasma malondialdehyde, total cholesterol, low- and high-density lipoprotein cholesterol, triglycerides, glucose, uric acid, ferritin and transferrin, together with routine red blood cell parameters. The effect of daily propolis intake seems to be time and gender related. For the men test group after the initial 15 days of propolis treatment, 23.2% (p=0.005) decrease in concentration of malondialdehyde was observed. After 30 days of treatment, statistically significant (p=0.010) 20.9% increase in superoxide dismutase activity and change in some of the red blood cell parameters were detected. For the women test group, the propolis treatment did not induce a change in any of the measured parameters.