Metformin is a medicine for the treatment of diabetes. Metformin is classified as a western drug, a hypoglycemic agent, used in patients with type 2 diabetes mellitus who are obese and with hyperinsulinemia, and in patients with type 2 diabetes mellitus who are not satisfied with dietary control alone. This product can lower blood sugar and it can reduce weight. Adverse effects of metformin: nausea and vomiting, diarrhea, abnormal sensation, dyspepsia, headache, dizziness, muscle pain, rash, weakness heart muscle and other adverse effects can occur. Contraindications: It is contraindicated in patients who are allergic to metformin. Metformin is contraindicated in patients with alcoholism, heart failure, acute myocardial infarction, sepsis-induced renal dysfunction. Precautions: patients with type 1 diabetes mellitus can not use metformin alone, and need to frequently measure fasting blood sugar, urine ketone bodies, urine glucose and other related tests before using the drug. Contraindicated in pregnant or lactating women. The use of metformin should be carried out under the guidance of a doctor, the occurrence of physical discomfort should be timely consultation, active treatment, so as not to delay the condition.