Regular insulin is the only human insulin that can be injected intravenously. Intravenous injection of regular insulin is mainly used in the following cases: 1) Rapidly lowering blood sugar, when blood sugar rises significantly, intravenous injection of saline plus a certain amount of regular insulin can rapidly lower blood sugar, mostly used for diabetic patients with significant blood sugar rise or combined with acute complications, such as diabetic ketoacidosis, diabetic hyperosmolar coma, etc., and need to quickly lower blood sugar. When diabetic patients cannot eat normally and need intravenous glucose injection, in order to improve the utilization rate of glucose and avoid further increase of blood sugar, ordinary insulin can be added into intravenous drip in the ratio of 1U insulin and 3-4g glucose. A certain amount of regular insulin can also be added when glucose injection is given to patients with normal blood sugar, which is beneficial to the utilization of glucose. In the process of intravenous drip of regular insulin, it is necessary to monitor blood sugar regularly to avoid hypoglycemia.