1, the representative drug of metformin class is metformin hydrochloride. It can reduce the output of hepatic glucose and improve peripheral insulin resistance it can make glycated hemoglobin drop 1 to 2%, can make weight loss can reduce the occurrence of cardiovascular events and reduce mortality in obese type 2 diabetic patients is the first-line drugs in the guidelines of various countries to control hyperglycemia in type 2 diabetic patients, and is the basic drug in the combination. Metformin alone does not cause hypoglycemia, but when combined with insulin or insulinotropic agents can increase the risk of hypoglycemia. The main side effects are gastrointestinal reactions, and the rare serious side effect is inducing lactic acidosis, so it is prohibited in patients with hepatic or renal insufficiency, serious infection, hypoxia or undergoing major surgery. 2. The representative drugs of sulfonylureas are glibenclamide, glimepiride, gliclazide, glipizide and glipizide. They are pro-insulin secretagogues, which stimulate the secretion of insulin by pancreatic beta cells to lower blood sugar levels. This class of drugs can reduce glycosylated hemoglobin by 1 to 2% and is the main drug used to control hyperglycemia in patients with type 2 diabetes in all countries’ guidelines. Improper use of sulfonylureas can lead to severe hypoglycemia in patients with type 2 diabetes, especially in older patients and those with hepatic and renal insufficiency. This class of drugs can also lead to weight gain. It is worth reminding that all kinds of sulfonylureas have different intensities and durations of action in the body, so be sure to take the medication as prescribed by your doctor and do not choose your own medication. The representative drugs of thiazolidinediones are rosiglitazone maleate and pioglitazone hydrochloride. This class of drugs can lower blood sugar by increasing the sensitivity of target cells to the action of insulin, and can make glycated hemoglobin fall by 1 to 1.5%. This class of drugs does not cause hypoglycemia when used alone, but can increase the risk of hypoglycemia when used in combination with insulin or proinsulin secretagogues. Weight gain and edema are common side effects, which are more obvious when used in combination with insulin. 4.Glinide drugs include Repaglinide, Naglinide and Miglinide. It is a non-sulfonylurea insulin stimulant, mainly after stimulating the early secretion of insulin to reduce postprandial blood glucose, which can cause glycated hemoglobin to drop by 0.3 to 1.5%, with the characteristics of fast absorption, fast onset of action and short duration of action, taken immediately before meals, and can be used alone or in combination with other hypoglycemic drugs (except sulfonylureas). Common side effects of glinides are hypoglycemia and weight gain, but hypoglycemia occurs less frequently and to a lesser extent than with sulfonylureas. Advantages: Patients with renal insufficiency can be applied. 5. The representative drugs of α-glucosidase inhibitors are acarbose, voglibose and miglitol. This class of drugs can lower postprandial blood sugar by inhibiting the absorption of carbohydrates in the upper part of the small intestine. They can reduce glycated hemoglobin by 0.5 to 0.8% and are suitable for patients with carbohydrates as the main food component and elevated postprandial blood glucose. It does not increase body weight and has a tendency to make weight loss. It can be combined with sulfonylurea, biguanide, thiazolidinediones or insulin. α-Glucosidase inhibitors commonly have adverse reactions as gastrointestinal reactions, such as abdominal distension and exhaustion, etc. Starting with small doses and gradually increasing the dose is an effective way to reduce adverse reactions. Such drugs are taken with the first bite of rice chewed together, so as to achieve the best results. 6, DPP-4 inhibitors on behalf of the drug is selegiline and saxagliptin. These drugs can reduce glycated hemoglobin by 1.0 percent and do not increase body weight. The use of DPP-4 inhibitors alone does not increase the risk of hypoglycemia. 7.GLP-1 agonists are represented by liraglutide and exenatide. Liraglutide can reduce glycated hemoglobin by 1 to 2% and exenatide can reduce glycated hemoglobin by 0.8%. These drugs need to be injected subcutaneously and can be used alone or in combination with other oral hypoglycemic drugs, which have significant weight-lowering effects while lowering blood sugar. The risk of hypoglycemia is not significantly increased by the use of these drugs alone. Common gastrointestinal adverse effects, such as nausea, are mild to moderate, mainly seen at the time of initial treatment, and gradually decrease with the duration of treatment. Exenatide is contraindicated in patients with a history of pancreatitis. It is especially suitable for obese diabetic patients. 8.All kinds of insulin preparations. Such as menthol insulin, eugenol, glargine insulin, etc.