Glargine insulin is a long-acting insulin, which is a hypoglycemic agent. Largin insulin has the characteristics of long-acting and smooth, without peak plasma drug concentration, and is mainly used for replacement therapy of basal insulin. Largin insulin can be used alone or in combination with short-acting insulin or oral hypoglycemic agents. The dose of glargine insulin varies from person to person, and the treatment should be injected once a day according to its characteristics of action, and it should be injected subcutaneously when used, not intravenously. Serious hypoglycemia can occur if the usual dose of subcutaneous injection is injected into the vein. Adverse reactions of glargine insulin include hypoglycemia, allergic reaction, malnutrition of fat at the injection site, etc. For elderly people with progressive renal hypofunction, the dose should be gradually reduced when using it. In addition, the use of this drug should not be mixed with any other drugs to avoid serious adverse reactions.