An object is to establish a method of preparation of novel polysaccharides from a cassis polysaccharide (CAPS), wherein the novel polysaccharides exhibit a higher immunoregulatory effect per unit amount, have a low viscosity, and can be handled readily during the method of preparation a final product. Another object is to provide health foods and drinks having high safety and an excellent immunoregulatory effect at a low cost by utilizing a juice, processed juice or a purified product. The present invention relates to a composition of which chief ingredient is novel polysaccharides, having an average molecular weight falling within a range of 10,000 to 40,000; which is obtained by partially digestion of CAPS with enzyme, and an immunoregulatory foods and drinks utilizing the composition.
