Objective: The polysaccharide was separated and purified from Paederia scandens for antibacterial polysaccharide in vivo. Method: The crude polysaccharides were separated and purified by column chromatography

and then the homogeneous polysaccharides were identified by gel column chromatography and polyacrylamide disc gel electrophoresis. Their structure was analyzed by GC and IR. The activities of polysaccharides were studied by antibacterial model in vivo. Result: Two kinds of homogeneous polysaccharides

PSP2a and PSP2b

were obtained from P. scandens. PSP2a were consisted of glucose

galactose

mannose

xylose and arabinose in the molar ratio of 4.92:3.23:1.00:1.73:3.50.PSP2b were consisted of arabinose

galactose and glucose in the molar ratio of 1.00:0.73:1.80.PSP2a and PSP2b mainly contained furanose. The antibacterial model in vivo indicated that PSP

PSP2 and PSP2a could protect mice infected with the resistant strain of P. scandens

and protection of PSP2a was best. Conclusion: The antibacterial component among polysaccharides from P. scandens was mainly PSP2a.