Many plant polysaccharide fractions have been reported as immunomodulatory agents. However, sometimes the possibility of contamination with bacterial lipopolysaccharide (LPS), a potent B cell mitogen and immune modulator, is discussed. In the present paper, we investigated the effects of crude polysaccharide fractions obtained from the shoot and hairy root of Glycyrrhizae sp. on murine peritoneal macrophage function, in order to clarify whether plants grown under aseptic conditions produce immunomodulatory polysaccharides. All crude polysaccharide fractions induced nitric oxide production by murine peritoneal macrophages in vitro. Chemical analysis revealed that LPS-like molecules were not present in all preparations. These results suggested that shoot and hairy root biosynthesized polysaccharides that could stimulate macrophages de novo.