Abstract:The scavenging effects of daphnetin (D) and its Cu ,Zn complexes on superoxide radical (O2) gener-ated through the photooxidation of riboflavin were studied with human red blood cells (RBC) and RBC membrane asexperimental material. The Cu(Ⅱ) complex showed the highest activity. SOD, D and its Cu (Ⅱ) ,Zn (Ⅱ) complexeswese found to have inhibitory effect on the production of lipid peroxide in the membrane ,SOD being the best amongthem.