If there is no obvious adverse reaction and the doctor did not ask to stop the drug, patients who have been taking metformin for a year should not stop treatment by themselves. Metformin belongs to the biguanide class of hypoglycemic drugs, which can be used to treat patients with type 2 diabetes who cannot control their blood sugar well by diet control and exercise alone. Adverse effects such as nausea, vomiting, abdominal pain, hypoglycemia, stool abnormalities and dizziness may occur after taking the drug. If there is no obvious adverse reaction after taking the drug, and the doctor has not asked to stop the drug, the patient should not stop taking Metformin on their own, so as not to cause the blood glucose to rise again, which is not conducive to the control of blood sugar, and if the long-term blood sugar control is not good may induce diabetic macrovascular disease, diabetic nephropathy and other serious complications. Patients who need to use metformin should be treated under the guidance of a doctor, and should not blindly stop or reduce treatment on their own.