This experiment was conducted to evaluate inhibitory effects against lung metastasis and promotion of splenocytes by water extracts from various mushrooms including Armillaria mellea, Grifola frondosa, Garnoderma frondosa, Codyceps militaris, Hericium erinaceus, Coriolus versicolor, Agaricus Blazei with Lycium Chinense Miller (known as M8). Analysis of carbohydrate using HPTLC showed that beta-glucan and pachyman were some of the major components of M8. Oral administration of M8 resulted in a dose-dependent tendency to inhibit lung metastasis after intravenous injection of colon26-L5 cells. Treatment with M8 resulted in a significant increase of T cell and B cell mitogenic stimuli. The population of CD3, CD19, CD4, and CD8 positive cells increased in a dose dependent manner of M8 administration. However, no significant results were obtained from the population of Mac-1 and NK1.1 positive cells. Oral administration of M8 resulted in the increased production of IFN-gamma and IL-4 by splenocytes stimulated with Con A compared with untreated controls. These results show that M8 has antitumor activities which may be useful as an antimetastatic agent.