The polysaccharide fractions were isolated and purified from Phellodendron chinese SCHNEID, and antitumor activities using the melanoma B-16-derived metastatic tumors were examined at dosages of 2, 5 and 10 mg/100 g. F-7 and F-8 showed the highest tumor metastatic inhibitory activities (inhibition ratio 60 and 80% in 2 mg/100 g), and in dose of 5 mg/100 g, the inhibitory ratios were 85 and 70%, respectively. Furthermore, 10 mg/100 g of intraperitoneal (i.p.) injection gave 90 and 95% of inhibition. When the effects of polysaccharides on hypersensitivity were examined, the inhibitory activities were not markedly observed in oral administration, indicating that the polysaccharides are directly acting to immune system. Also, the polysaccharides increased the number of circulating blood leukocytes and total peritoneal exudate cells. Although implantation of tumor cells greatly decreased the productivity of antibody (antibody-mediated) and T lymphocyte reactivity (delayed-type) as 6.3 from 9.3 and 5.9 from 7.7, represented by the increase of footpad thickness, respectively. the polysaccharides elevated the reactivity of T lymphocyte in tumor-bearing mice, which were rapidly recovered by discontinuance of sample treatments. Especially, F-2, F-5, F-7 and F-8 remarkably recovered the decreased sensitivity. These results clearly indicated that the i.p. injection is much effective to suppress tumor growth than oral administration.