Oxidative stress plays an important role in chronic complications of diabetes. Acarbose is an alpha-glucosidase inhibitor used for the treatment of diabetes. A commercial herbal formulated extract, which consists of 13 herbal extract (F13), is also described to have a potential antidiabetic action. The aim of this study was to determine the comparative effects of acarbose and F13 on type 2 diabetic rats. Three to five weeks after induction of diabetes by single dose systemic administration of streptozotocin and nicotinamide (STZ-NA), diabetic rats were treated with acarbose and F13 for two weeks. After the treatment period, the blood glucose, hemoglobin A1c (HbA(1)c), triglyceride, cholesterol and nitric oxide synthases (NOS) levels, as well as liver and erythrocyte superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT) and glutathione peroxidase (GPx) levels were determined. Renal filtration changes were determined by measuring urine creatinine, plasma creatinine and creatinine clearance. Histological analyses were also performed in liver and kidney. The rats in diabetic groups had significantly higher blood glucose levels than control groups. Induction of diabetes was confirmed by histological analyses of liver and kidney tissues. High blood glucose level in diabetic rats results in peroxidative reactions in lipids, thus MDA levels were increased in diabetic control while acarbose and F13 treatment reduced MDA production. Also, increased SOD levels were found in STZ-NA diabetic rat liver. Both acarbose and F13 treatment, however, showed similar improving effects on diabetic complication in diabetes. Our results, therefore, support the validity of this herbal extract on the management of diabetes as well as diabetes-induced liver and renal complications.