Protein-containing polysaccharides extracted from fruiting bodies of a Chinese fungus named Feng Wei Gu, were fractionated and purified, and their antitumor activities were tested, out of which the following active fractions were obtained. FIo-a: A protein-containing xyloglucan, MW 280,000, polysaccharide: protein = 76:24 (w/w), polysaccharide consisting of Man:Gal:Xyl:Glc = 2:12:42:42 (molar ratio). [alpha]D23 + 25.3 degrees. FA-2: A protein-containing mannogalactan, MW 120,000, polysaccharide: protein = 76:16 (w/w), consisting of Xyl:Man:Gal = 9:35:56 (molar ratio), [alpha]D23 + 98.5 degrees. FII-1: A Protein-containing xylan (62:21 w/w). MW 200,000, [alpha]D23 + 8.7 degrees. FIII-1a: A protein-containing glucoxylan (15:71 w/w), [alpha]D23 + 30.7 degrees, MW 90,000, consisting of Glc:Xyl = 40:44 (molar ratio). FIII-2a: A protein-containing xyloglucan, MW 70,000, polysaccharide:protein = 69:3 (w/w), polysaccharide consisting of Xyl:Glc = 36:62 (molar ratio). [alpha]D23 + 38.6 degrees.