Oral hypoglycemic drugs for diabetes mainly include the following categories: 1. Metformin drugs This kind of drug belongs to insulin sensitizers, mainly by reducing the output of liver glucose to lower blood sugar. The commonly used drugs are metformin. It is suitable for obese and overweight type 2 diabetic patients. Common adverse reactions include gastrointestinal reactions, occasional allergic reactions, and can occasionally induce lactic acidosis in cases of hypoxia such as hepatic and renal insufficiency, hypovolemic shock and heart failure, and should be used with caution. Metformin is the cornerstone of diabetes treatment guideline drugs at home and abroad. It has a good safety profile, and many clinical trials at home and abroad have confirmed in a meta-analysis that there is no evidence that metformin can increase the risk of lactic acidosis. Many patients are concerned about the effects of long-term metformin use on the kidneys. In fact, the drug has no direct damaging effect on the kidneys, only that it can lead to drug accumulation when taken by patients with existing kidney damage. In addition, metformin only reduces high blood sugar, no hypoglycemic effect on people with normal blood sugar, monotherapy will not cause hypoglycemia. In addition, metformin has no carcinogenic and mutagenic effects. 2.Sulfonylureas These drugs are insulin secretagogues, which mainly increase the secretion of insulin to lower blood sugar. Commonly used drugs include gliphenylurea, gliclazide, glipizide, glipizide, glipizide and glimepiride. They are mainly used for non-obese patients with type 2 diabetes. The common adverse effects are hypoglycemia and weight gain can occur in long-term users. In this class of drugs gliphenylurea elderly use need to be cautious, because it is prone to more serious hypoglycemia, and will last a long time. 3, glinepiride drugs These drugs are insulin secretagogues, mainly by stimulating the early secretion of insulin phase to reduce postprandial blood sugar, characterized by fast absorption, fast onset of action, and short duration of action. Commonly used drugs include Repaglinide, Naglinide, etc. The common adverse effect is hypoglycemia. 4.α-glucosidase inhibitors These drugs mainly slow down the absorption of carbohydrates by inhibiting intestinal α-glucosidase and reduce postprandial hyperglycemia. The commonly used drugs are acarbose, voglibose and so on. It is mainly applied to patients with mainly postprandial hyperglycemia. Common adverse reactions include gastrointestinal reactions, such as bloating, diarrhea, excessive exhaustion, etc. 5, thiazolidinediones These drugs belong to insulin sensitizers, mainly through improving insulin resistance, is the tissue to increase the sensitivity of insulin and achieve the effect of lowering sugar. The commonly used drugs are rosiglitazone maleate or pioglitazone hydrochloride. It is mainly used in early diabetes and type 2 diabetes with certain amount of presence in the body. Common adverse effects include edema and weight gain, which can lead to aggravation of heart failure in patients with existing heart failure and should not be used in patients with cardiac function grade III-IV. 6.Intestinal proinsulin mainly promotes the secretion of insulin, inhibits the secretion of glucagon and regulates the feeding center. It is a kind of pancreatic glucagon-like peptide, also called human glucagon-like peptide-1 analogues, such as: liraglutide, exenatide and so on. It can better control blood sugar and reduce body weight, the main adverse effects are gastrointestinal reactions, nausea, vomiting and abdominal pain, etc. 7. Dipeptidyl peptidase IV inhibitor DPP-4 is a kind of enzyme in the body, also known as enzyme. It is a new drug for the treatment of type 2 diabetes marketed in recent years,DPP4 inhibitor has the effect of increasing GLP-1 activity, improving glucose and lipid metabolism, reducing β-cell apoptosis and promoting β-cell proliferation. There are several DPP-4 inhibitors, such as sitagliptin, saxagliptin, vildagliptin, ligliptin and alogliptin. The chemical structure and pharmacokinetics of these drugs may vary, but they are all effective in lowering blood glucose and are well tolerated. dPP4 inhibitors have the unique advantage of acting on new targets and will be an excellent new class of anti-diabetic drugs.