In order to investigate the effects of Kyegyoksan on antitumor effects after Sarcoma 180 cells transplantation into the peritoneal cavity or left groin in mice, and immune depression in mice induced by methotrexate, the extracts of its herbal medicines were orally administered for 14 or 21 days. Experimental studies were performed for measureance of $IC_{50}$ in MTT assay, mean survival days, tumor and body weights for antitumor effects, delayed type hypersensitivity, hemagglutinine titer, hemolysin titer, rosette forming cells, interleukin-2 productivity, lymphocyte transformation, natural killer cell activity and phagocytic activity for immune responses in the immune depressed ICR mice, and SGOT, SGPT, BUN and creatinine for liver and kidney protective function in SO-rats. The results were obtained as follows: 1. From the results of MTT assay, the Kyegyoksan exstracts for SUN-1 and SUN-C4 were inhibited cell viability. 2. Mean survival time in Kyegyoksan-treated group was slightly increased with no effectiveness, as compared with the control group. 3. Tumor weight in Kyegyoksan-treated group was depressed with the statistical significance, as compared with the control group(p<0.01). 4. Body weight in Kyegyoksan-treated group was incresed with the statistical significance, as compared with the control group(p<0.05). 5. Delayed type hypersensitivity in Kyegyoksan-treated group was slightly incresed with no effctiveness, as compared with the control group. 6. Hemagglutinin titer in Kyegyoksan-treated group was incresed with the statistical significance(p<0.05), but hemolysin titer was slightly incresed with no effectiveness, as compared with the control group. 7. Rosette forming cells in Kyegyoksan-treated group was incresed with the statistical significance, as compared with the control group(p<0.001). 8. Interleukin-2 productivity in Kyegyoksan-treated group was incresed with the statistical significance, as compared with the control group(p<0.001). 9. Lymphocyte transfomation in Kyegyoksan-treated group was incresed with the statistical significance, as compared with the control group(p<0.01). 10. Natural killer cell activity in Kyegyoksan-treated group at E/T ratio 100 : 1 was incresed with the statistical significance(p<0.01), but at E/T ratio 50 : 1 and 10 : 1 was slightly incresed with no effectiveness, as compared with the control group. 11. Phagocytic activity in Kyegyoksan-treated group was slightly incresed with no effectiveness, as compared with the control group. 12. The levels of serum glutamic oxalacetic transaminase, serum glutamic pyruvic transaminase, blood urea nitrogen and serum creatinine in Kyegyoksan-treated group were not effective change, as compared with the control group. According to the above results, it could be suggested that Kyegyoksan have prominent antitumor effects, enhance both cellular and humoral immunity, and have no injury to liver and kidney functions.