Black radish (Raphanus sativus L. var. niger) root has been used in folk medicine since antiquity as a natural drug for the stimulation of bile function. According to in vitro studies the squeezed juice from black radish root exhibited significant antioxidant properties. In the present study, the beneficial effect of the black radish juice on some free radical reactions in rats fed with a diet rich in lipids (20% sunflower oil, 2% cholesterol, 0.5% cholic acid in normal chow) was examined. Thiobarbituric acid reactive substances and conjugated diene concentrations were significantly higher, while the antioxidant enzyme activities and the free radical scavenging capacity were lower in hyperlipidaemic rats compared with normal controls. Supplementation of the lipid-rich diet with black radish juice resulted in a significant improvement of the parameters mentioned above. Although the exact mechanism of the biologically active compounds in black radish on the lipid metabolism and lipid peroxidation is not clear yet, a beneficial effect of the drug was evident in alimentary hyperlipidaemia.