There are many situations in which oral hypoglycemic agents are inappropriate, some are absolutely inappropriate, some are only relatively inappropriate, or the instructions should be quite careful. These situations include: (1) insulin-dependent diabetic patients should not use oral hypoglycemic drugs alone, but of course, biguanide hypoglycemic drugs and Bystolic combined with insulin is still very effective; (2) pregnant women with diabetes should always stop using oral hypoglycemic drugs to avoid poor glycemic control, and at the same time cause abnormal fetal development. Because oral hypoglycemic drugs can be excreted through breast milk, so breastfeeding women should not take oral hypoglycemic drugs; (3) liver and kidney function is not used or cautious use of oral hypoglycemic drugs, all oral hypoglycemic drugs must be metabolized by the liver, most of them have to be excreted through the kidneys, patients with poor liver and kidney function taking oral hypoglycemic drugs may occur drug accumulation poisoning or hypoglycemia, and may further damage liver and kidney function; (4) acute complications of diabetes: such as diabetes mellitus and insulin are still very effective; (5) diabetes mellitus is not used. (4) acute complications of diabetes mellitus: such as infection, diabetic ketoacidosis, hypertonic non-ketotic diabetic coma, etc. The effect of using oral hypoglycemic drugs is very poor, and some of them may aggravate ketoacidosis or cause lactic acidosis, so it is better not to use them; (5) more serious chronic complications of diabetes mellitus, especially those who have developed stage III or more renal and fundus lesions should stop using oral hypoglycemic drugs and use insulin instead (6) other emergencies: such as myocardial infarction, surgery, trauma, etc., should also be changed to insulin therapy for a short period of time.