The proliferation of splenic lymphocytes, the humoral immune response to sheep red blood cells and the phagocytotic function of intraperitoneal macrophages of mice were all stimulated by ig the flesh of Meretrix meretrixL. (FM) 20 g/kg and 10 g/kg for 7 days. FM 20 g/kg and 10 g/kg ig for 15 days also enhanced the activity of serum T-SOD, and decreased the level of serum MDA in old mice. The anti -stress effect of FM, such as increasing the swimming time of mice in 20癈 water by ig FM 20 g/kg and 10 g/kg for 7 days, was also achieved.