Barberries (Berberis integerrima), the tart, red fruits that grow on bushes, have been used for centuries in traditional medicine for digestive issues, and now evidence has emerged from Iranian researchers that barberry extract can help lower Type 2 diabetes markers. For eight weeks, 30 patients were given 1,000 milligrams of barberry extract daily, along with the standard anti-diabetic medication metformin, while another 35 patients were given only metformin. Afterwards, fasting blood sugar levels were significantly lower among the barberry group as were HbA1c levels, which measure blood sugar levels for two to three months.