The purpose of this study is to investigate the effects of Ginseng saponin on the cadmium which is widely distributed in the environment, results in immune system alteration. For the experiments, 125 mice of ICR strain were used. The experimental groups were divided into 5 groups a control, a cadmium alone treatment group, three Cd and saponin (10, 50, 100 mg/kg) combined treatment groups. The mice were allocated 25 to each group and observed for 8 weeks. The results of experiment are as follows: 1. Body weight growth rates during 8 weeks were as this control group 36.47%, Cd alone group 32.48%, saponin combined treatment group (10, 50, 100 mg/kg) 32.49%, 39.17%, 24.27% respectively. 2. In all groups, the relative weights of liver and kidney were increased, compared with control group. In the case of spleen, saponin combined treatment group (50, 100 mg/kg) was high to the significant level compared with a control group (p<0.05). Thymus was not. 3. On blood lymphocyte count observation, Cd alone treament group has 25.6% less than control group, and saponin combined treatment group have increasing trends. but in thymus and spleen, there was no trends like blood. 4. On antibody titer, there was no difference among groups. 5. On total serum protein, saponin (100 mg/kg) combined treatment group was high to significant level compared with control group (p<0.05), and other treatment groups have increasing trends. 6. Cd accumulation in kidney was higher than in liver, and all treatment groups were high to the very significant level compared with the control group (p<0.05), but there was no difference among groups. From the results of this study, it can be concluded that the oral administration of Cd results in alteration of immune system and Ginseng saponin prevents this effect. But, Cd accumulation was not affected by saponin.