Water-soluble pectins isolated from Trichosanthes Rhizoma and Taraxii Herba and their deproteinized polysaccharides were purified through DEAE cellulose column and were applied to immunopotentiating and antitumor studies to clarify the nature of their activities of our previous reports. As the results of works, the lectins and deproteinized polysaccharides increased the number of circulating leukocytes and total peritoneal cells. And they markedly elevated the lowered production of antibody and reactivity of T Iymphocyte in tumor-bearing mice, which were rapidly recovered by discontinuance of sample treatments. They also decreased the growth of Sarcoma 180 solid tumor in mice.