Metformin is commonly used in diabetic patients, the dosage is usually 0.5g each time, 2-3 times/day, not more than 2.5g per day, otherwise it will easily bring adverse effects to the body. The function of metformin is mainly to promote the absorption and utilization of glucose in the surrounding tissues, so as to achieve a better effect of lowering blood sugar in the body. There are certain contraindications to the use of this drug, and metformin should not be used if patients suffering from severe liver and kidney insufficiency. It should also be noted that patients with acute complications, such as lactic acidosis and ketoacidosis, should not take this drug. Metformin is a safe and effective hypoglycemic drug, but it should be noted that its contraindications, the use of this drug is best under the guidance of a doctor to take reasonable.