Diabetic patients are usually allowed to take metformin under the guidance of a doctor, but need to pay attention to the indications and contraindications of the drug. Metformin is used in patients with type 2 diabetes mellitus whose dietary control alone is unsatisfactory, especially those who are obese and with hyperinsulinemia, with this drug not only has a hypoglycemic effect, but also may have the effect of reducing weight and hyperinsulinemia. Common adverse reactions include nausea, vomiting, diarrhea, abnormal taste, and sometimes abdominal pain, constipation, bloating, dyspepsia, heartburn, as well as dizziness, headache, flu-like symptoms, muscle aches, low blood pressure, flushing, chills, chest discomfort, rash, malaise, fatigue. Metformin is contraindicated in patients with severe infections and trauma, surgery, clinical hypotension and hypoxia. Patients diagnosed with diabetes mellitus should actively cooperate with the doctor’s treatment, patients who need to take Metformin are recommended to consult a professional doctor before taking it.