Insulin can be injected intravenously, and the insulin that can be injected intravenously is short-acting insulin. Insulin is a hypoglycemic hormone and can be divided into short-acting insulin, intermediate-acting insulin, long-acting insulin and premixed insulin depending on the duration of action. Insulins that can be injected intravenously are short-acting insulins, also known as regular insulins, regular insulins, etc., or R for short, including animal-derived regular insulins and regular recombinant human insulins. Intermediate-acting insulins, long-acting insulins, and premixed insulins, are not available for intravenous injection. Intravenous insulin has a rapid onset of action and short maintenance time, and provides rapid and effective blood glucose control. The situations that require intravenous insulin include the following: First, intravenous insulin can be administered to diabetic patients when their blood glucose rises significantly, in order to achieve rapid reduction of blood glucose. Second, when diabetes is combined with acute complications such as diabetic ketoacidosis and hyperosmolar coma, intravenous insulin is also needed to control blood sugar as soon as possible. Third, diabetic patients who cannot eat need intravenous glucose solution and insulin to provide the carbohydrates needed by the body to avoid further increase of blood sugar.