This chapter deals with non-clinical studies of immunostimulating polysaccharides using a particular kampo medicine, Juzen-Taiho-To (JTT), as an example, and recent advances in the study of bioactive polysaccharides in component Chinese and Japanese herbs, using an anti-polysaccharide antibody. JTT has been administered to patients with anemia, anorexia or a debilitated general condition caused by surgery, chronic disease or childbirth. The clinical effects observed suggest that JTT enhances immune responses and improves the functioning of hemopoietic systems. Of the ten component herbs in JTT, Glycyrrhizae Radix contains the most potent mitogenic polysaccharide, and the purified polysaccharide has chemical properties similar to those of the active polysaccharides in F-5-2, although some other herbs also contain the active polysaccharide fractions. Several pharmacological activities have been observed in pectic polysaccharides such as pectins, pectic arabinogalactans and pectic heteroglycans in addition to low molecular-weight substances from some kampo formulas and their component herbs.