PIP60-1, a novel heteropolysaccharide isolated from fruiting bodies of the medicinal fungus, Phellinus igniarius, has a molecular weight of 1.71×10 4 Da and is composed of l-fucose, d-glucose, d-mannose, d-galactose and 3-O-Me-d-galactose in a ratio of 1:1:1:2:1. A structural investigation of PIP60-1 carried out using sugar and methylation analyses, combined with 1 H and 13 C NMR spectroscopy, including COSY, TOCSY, NOESY, HSQC and HMBC experiments, established the repeating unit of the polysaccharide as the following: