Metformin is used in different doses depending on the blood sugar. Metformin clinically used there are three specifications: zero.5 grams and zero.25 grams, zero.85 grams, early diabetes blood sugar is relatively good, use zero.5 grams once a day. If the patient has no adverse reactions or bad blood sugar control, you can add to zero.5 grams twice a day, if the blood sugar still can not be lowered, the maximum dose can be used to two grams. But the use of metformin must be in the case of normal liver function, kidney function can be used, its adverse reactions are nausea, vomiting, poor appetite, more serious can cause lactic acidosis.