If a glucose-lowering drug alone cannot effectively control blood sugar, a combination of drugs can generally be considered to control blood sugar. And there are great advantages of the combination drug scheme. Here we talk about the advantages and indications of the combination of drugs. 1, the combination of sulfonylurea and biguanide: good effect of sugar reduction and low cost, the effect of fasting and postprandial blood sugar is relatively strong. 2.Sulfonylurea and α-glucosidase inhibitor combination: suitable for patients whose postprandial blood sugar cannot be controlled by sulfonylurea alone, and the effect is better for patients with high postprandial blood sugar. 3.Biguanide combined with thiazolidinediones: This combination is more suitable for patients with hyperinsulinemia, that is to say, high insulin level, abnormal blood sugar and obvious insulin resistance. 4.Biguanide combined with DPP-4 inhibitor: it not only has good hypoglycemic effect and does not cause hypoglycemia, but also does not increase weight. Of course, the combination of drugs is also delicate, generally two is more appropriate, more than three is appropriate, if the combination of too many types of drugs, or too large a dose of drugs, will produce significant side effects, damage to the liver and kidneys is also a problem that needs attention.