Insulin long-term use may appear hypoglycemia, injection site infection, lipodystrophy and other side effects. 1 Hypoglycemia: the use of insulin dosage is related to the amount of food intake, according to the changes in blood glucose and timely adjustment of insulin dosage. Some diabetic patients, after making a good insulin regimen, did not monitor their blood glucose, had irregular diets, continued to use the original dose of insulin, and finally developed hypoglycemia. 2. Injection site infection: diabetic patients need to inject insulin by themselves, and some of them, in order to save money, use needles repeatedly and do not sterilize the injection site according to the regulations, which leads to the infection of the injection site. 3. Fat malnutrition: subcutaneous fat atrophy or hyperplasia at the injection site, which needs to be injected in a different site to make it recover slowly. Insulin is mainly used in the treatment of diabetes mellitus, and is prohibited for hypoglycemia and insulin allergy. The use of insulin, must be used in accordance with medical advice, regular monitoring of blood glucose.