Insulin can not be placed in the refrigerator after opening, but it needs to be placed at room temperature below 25℃ for a maximum of 4 weeks. Insulin is a commonly used clinical hypoglycemic hormone, mainly for type 1 diabetes and type 2 diabetes where oral hypoglycemic drug treatment is ineffective, and gestational diabetes, etc. The use of insulin must be carried out under the guidance of a doctor. When insulin needs to be placed for a long time, it should be placed in the refrigerator at a temperature of 2-8°C to avoid excessive temperature fluctuations and freezing. If insulin has been opened it can not be placed in the refrigerator, insulin can be kept at room temperature below 25℃ for 4 weeks. Therefore, if the opened insulin is not placed in the refrigerator, whether it can be used again depends on the temperature and time of placement. If the storage temperature is too high and continues to exceed 25℃, or if the storage time has exceeded 4 weeks, it is not recommended to continue to apply it. If the storage temperature is below 25℃ and the storage time does not exceed 4 weeks, it is still possible to continue to apply.