Diabetes is a prevalent health concern all over the world, which is also constantly on the rise. The prevalence of diabetes is expected to rise from 4% in 1995 to 5.4% in 2025. More than five million individuals suffer from diabetes in Iran. This disease results in handicap, morbidity and considerable long-term consequences, and is an important risk factor for cardiovascular diseases. Considering the rise in obesity in children and adults today, diabetes seems to become more prevalent over the next decade. Therapeutic goals in diabetic adults include: glycemic control (HbA1C<7%, fasting blood sugar 70-130 and blood sugar after meals less than 180 mg/dl), blood pressure control (under 80:130 mm Hg) and blood lipid control (LDL under 100, HDL over 40 in men, over 50 in women, triglyceride under 150 mg/dl); therefore, a variety of drugs and diets are used. Herbal drugs are commonly used as adjuvant treatments for diabetes. Out of 26 plant species used for treatment of diabetes, walnut, saltbush, olive and stinging nettle are strongly recommended; therefore, they have been used in the formulation of Glucoherb Barij® Tablet. The safety of these four plants is testified by their log use in various nations. There is evidence of the cure of high blood sugar using the tannins and the phenolics in walnut leaves both in Europe and Southwest Asia. In in vivo and in vitro studies, the safety and efficacy of Glucolevel tablet (a product similar to Glucoherb Barij®) has been studied in blood sugar reduction: in HDL test, in human fibroblasts treated by high doses of this drug, no toxic effect was seen. In in vivo studies, similar results were observed in rats (LD50: 25g/kg). Considering the intensification (duplication) of glucose uptake by yeast cells and inhibition of intestinal absorption of glucose (about 49%) in rat intestine, the antidiabetic effects of this drug has been demonstrated. Furthermore, in comparison with positive control, with 2-3 weeks of treatment in streptozotocin-induced diabetic rats, the drug caused considerable reduction in blood sugar (from more than 400±50 mg/dl to 21o±22 mg/dl, p<0.001) and considerable improvement in glucose uptake in glucose tolerance test. In addition, in 16 volunteers aging 48-67 diagnosed with type II diabetes, who were only receiving diet therapy, the use of 3 tablets per day for 4 weeks resulted in considerable reduction in base blood sugar from in the first week of the treatment. In the beginning of the study, the blood sugar of a group of 11 participants was less than 300 and in the rest more than 300 mg. Clinically acceptable blood glucose levels were reached in the first group within 2-3 weeks of treatment and in the second group within four weeks. No adverse effects were reported. Furthermore, considerable reduction in in HbA1C was observed in 6 individuals (from 8.2±1.03 to 6.9±0.94). The results of this study demonstrated the safety, patient compliance and the efficacy of the combination of herbs in the drug, which seem to have different mechanisms for regulating glucose homeostasis, but have synergistic effects and result in natural balancing of blood sugar. The possible mechanism of the plants used in this drug can be as follows: The main active ingredient in olive leaves is oleuropeoside, which, with a dose of 16 mg/kg, apart from lowering blood pressure and blood lipids, has detectable hypoglycemic effects. The tannins and polyphenols in walnut leaves are strong antioxidants and are responsible for effective collection of superoxide and hydroxyl radicals. In an animal model of diabetes and obesity, it has been demonstrated that saltbush is an effective antidiabetic agent, which also enhances the effect of insulin. Stinging nettle extract has hypoglycemic effects and improves glucose tolerance. In vitro studies have shown that this drug facilitates the entrance of glucose to yeast cells during anaerobic fermentation; this effect has been attributed to the presence of saltbush in the drug. Stinging nettle may reduce production of glucose in the liver, while the oleuropein in olive leaves and the tannins in walnut leaves act as alpha-glucosidase inhibitors and reduce carbohydrate absorption in the intestines.