Elderly diabetes over 70 years old can generally take metformin, but need to be used with caution, discretion to reduce the amount of specific medication as prescribed by the doctor. Metformin is commonly used in clinical hypoglycemic drugs, suitable for patients with type 2 diabetes who have poor glucose-lowering effect through diet control or exercise therapy alone, in addition to sulfonylureas or insulin combined application to regulate blood glucose. Common adverse reactions include nausea, vomiting, fatigue, diarrhea, abdominal distension, headache and so on. Current contraindications to the use of the drug include renal disease or renal insufficiency caused by cardiovascular failure, acute infarction and sepsis; type 2 diabetes mellitus with ketoacidosis; major surgery, serious infections and traumas; severe functional insufficiency of vital organs; vitamin B12 or folic acid or iron deficiencies; alcoholics; and pregnant and lactating women. The drug is available from several manufacturers, and the drug inserts for each recommend that elderly patients use the drug with caution and reduce the dosage as appropriate, although there are some variations in the age limits for the elderly. Overall, however, older patients over the age of 70 should use the drug with caution and reduce the dosage as appropriate. Specific medications related to metformin should be administered under the supervision of a specialist.