Hypoglycemic efficacy of natural functional mixture(FM) and level of the diabete related hormones in streptozotocin(STZ)-induced diabetic rats were investigated. Male Sprague-Dawley rats were divided into three groups (normal, diabetic fed diets with/without FM). Supplement of FM did not affect the body weight and feed intake of STZ-induced diabetic rats. The increase in the weight of liver of STZ-induced diabetic rats was weakened by supplement of FM, whereas the weight of kidney and heart was not affected. Blood glucose level was slightly, and glucose tolerance of post-feeding was significantly improved by functional mixture. The mixture significantly reduced the elevated HbA1C level of diabetic rats by 15%, and it increased the level of insulin and C-peptide in blood and decreased glucagon level. Therefore, we conclude that FM in this study has a potency of prevention and treatment of diabetes mellitus.