In the brain homogenate system (experiment 1), addi tion of sericin was found to depress the concentration of TBARS (Fig. 1), while the addition of BSA only slightly depressed the concentration of TBARS. The course of lipid peroxidation in the homogenate system with or without 0.3% sericin is presented in Fig. 2 (experiment 2). The results clearly showed lower levels of TBARS and conjugated diene after sericin addition to the homogenate. In accordance with the results in experi ments 1 and 2, 0.3% sericin completely depressed the production of TBARS in the phosphate buffer system containing arachidonate, Fe3+, and ascorbate (experiment 3, Fig. 3).