The presence of plant extracts of Solanum nigrum and Cichorium intybus in the reaction mixture containing calf thymus DNA and free radical generating system protect DNA against oxidative damage to its deoxyribose sugar moiety. The effect was dependent on the concentration of plant extracts. However, the effect of Cichorium intybus was much pronounced as compared to the effect of Solanum nigrum. These studies suggest that the observed hepatoprotective effect of these crude plant extracts may be due to their ability to suppress the oxidative degradation of DNA in the tissue debris. © 1995.