Metformin may cause some liver and kidney damage, but it is usually rare. If metformin is used in patients with liver and kidney insufficiency, it may cause some harm and may aggravate the condition. Metformin is a glucose-lowering drug, commonly used in the treatment of diabetes, and is relatively safe in clinical application, with no serious damage to liver or kidney function, and can be safely taken by most diabetic patients. However, some patients may experience adverse reactions such as nausea, vomiting, diarrhea and abnormal taste. Although metformin does not have significant damage to liver and kidney function, it must be used with caution if the patient has decreased kidney function, or it may increase the risk of lactic acidosis. It must also be used with caution if the patient has severe liver disease, which may be potentially risky. Metformin should always be used under the supervision of a doctor.