It is not acceptable to continue using insulin for a month without using it up. Insulin is a drug that acts on the endocrine system to treat diabetes, which can reduce the source of glucose in the blood and increase its consumption, thus lowering blood sugar. However, insulin is a protein-based active substance, and one month after unpacking the active substance may become ineffective, and the effect on lowering blood sugar will be greatly reduced. It may also become a foreign protein, causing local reactions such as redness, swelling and allergy, and therefore should not be continued. Application of insulin may cause allergic reactions, redness and swelling at the injection site, hypoglycemic reactions, sweating, fat atrophy at the injection site and other adverse reactions. It is contraindicated for those who are allergic to insulin. Unopened insulin can be stored away from light during the shelf life, but it needs to be stored under refrigeration at 2~10°C. Note that it must not be frozen, because a lower temperature environment may cause insulin to freeze and lose its efficacy. Before applying insulin, it should be taken out of the refrigerator and left at room temperature for a period of time, and then injected when the temperature of insulin is close to the room temperature, so as not to irritate the skin. When using insulin, it is necessary to follow the doctor’s instructions for the rational use of medication, not self-medication.