This study was performed to investigate the effects of Fomitopsis pinicola extract on blood glucose and lipid metabolism in diabetic rats. The blood glucose concentration was similar to that of the control at 30 min, but after 60 min of glucose administration the blood glucose concentration rapidly decreased, and after 120 min was 100.7±4.0 mg/dL, representing an approximate 50% decrease compared to the control. In the case of the diabetic rats induced by streptozotocin, the concentration of blood glucose was decreased from 362.0±16.7 to 204.5±11.4 mg/dL after 20 days of administration. HDL- and LDL-cholesterol concentrations were 39.0±4.3 mg/L and 13.2±3.4 mg/dL, respectively, representing an approximate increase of 73% and approximate decrease of 76%, respectively, compared to the control. The activities of aspartate aminotransferase and alanine transaminase were increased. On the other hand, activities of amylase, alkaline phosphatase, lactate dehydrogenase, glutamic oxaloacetic transaminase, and glutamic pyruvic transaminase were decreased compared to that of the control. No difference was evident between test and control rats with respect to white blood cell, red blood cell, hemocyte, hemoglobin, hematocrit, and platelet counts. These results indicate that F. pinicola extract is useful as a preventative and treatment agent for damage of liver and kidney cells.