Abstract: The effect of 3,4-dihydroxyddacetophenone on hemolysis of erythrocytes induced by active oxygen radicals is presented. When erythrocytes were exposed to active oxygen generated in vitro, hemoglobin was broken down, lipids were peroxidated and hemolysis occured. These reactions were inhibited by 3,4-dihydroxyacetophenone. The results showed that 3,4-dihydroxyacetophenone might act as a scavenger of superoxide and hydroxy radical and might be used as an antioxidant.