Pre-meal blood glucose here may refer to fasting blood glucose, the elderly fasting blood glucose 13mmol / L is more than the normal blood glucose range, need to consult a doctor in a timely manner to clarify the condition, if the diagnosis of diabetes mellitus, under the guidance of the doctor to take insulinotropic secretagogues, bisphosphonates, thiazolidinediones, dipeptide dipeptidyl peptidase 4 inhibitors and other control of glucose, but also may be subcutaneous injection of insulin therapy. 1. Insulinotropic agents: glipizide, gliquidone. Contraindicated in children with diabetes mellitus, pregnant and lactating women, perioperative major surgery, and allergic patients. Adverse reactions include hypoglycemia, rash, skin itching, epigastric discomfort. 2. Metformin drugs: commonly used drugs are metformin. Pregnant women, lactating women, hepatic and renal insufficiency, hypoxia, hyperthermia, allergy, alcoholism can not be used. Adverse reactions include gastrointestinal reactions, skin allergic reactions, lactic acidosis, etc. Long-term use may lead to vitamin B12 deficiency. 3. Thiazolidinediones: rosiglitazone, pioglitazone. Children, pregnant women, lactating women are prohibited. Adverse effects include weight gain and edema, and are also associated with increased risk of fractures and heart failure. 4. Dipeptidyl peptidase 4 inhibitors: saxagliptin, selegiline. Not to be used in pregnant women, children and allergic individuals. Adverse reactions such as headache, hypersensitivity reactions, elevated liver enzymes, pancreatitis, and arthralgia may occur. 5. Sodium-glucose cotransporter protein 2 inhibitors: dagliflozin, canagliflozin. This product is contraindicated in people with a history of severe hypersensitivity reactions to this product. Adverse reactions include genitourinary tract infection. 6. Insulin: including long-acting insulin, short-acting insulin, etc. Adverse reactions may be hypoglycemia, etc., need to be selected under the guidance of the doctor. Elderly people with preprandial blood glucose 13mmol/L should go to the hospital in time and follow the doctor’s instructions for diagnosis and treatment.