The fruiting body and culture broth of many edible mushrooms contain water-soluble polysaccharides. Numerous researchers have reported that these polysaccharides have immunoenhancing effects. In this study, Hericium erinaceus and Hericium laciniatum were separately cultivated in a shaker at 25 degrees C for 25 days. Polysaccharides were extracted from the culture broth. The molecular weights were larger than 1 x 10(5) k Da and their polysaccharide components were mainly glucose in H. erinaceus and galactose in H. laciniatum. Furthermore, we investigated these two purified water-soluble polysaccharides for their anti-artificial pulmonary metastatic tumor and immunoenhancing effects in ICR mice. The results revealed that both polysaccharides had significant anti-artificial pulmonary metastatic tumor effects in mice (p < 0.05). Additionally, the polysaccharide from H. erinaceus was more effective than that from H. laciniatum. However, both of the polysaccharides enhanced the increase of T cells and macrophages. The numbers of CD4+ cells and macrophages were significantly higher in the test group than in the control group (p < 0.05). From our results, no differences were found between the two purified water-soluble polysaccharides in the antitumor effects and immunoenhancing activities (p > 0.05).