Insulin is an important method to control blood sugar. Patients who need insulin have the following categories: i. Patients with type 1 diabetes need insulin therapy throughout their lives. Second, type 2 diabetic patients need insulin therapy when oral medication control is ineffective. Third, type 2 diabetes combined with acute complications, such as diabetic ketoacidosis, hyperosmolar coma, or combined with chronic complications, such as retinopathy, diabetic nephropathy, etc. also need insulin therapy. Fourth, insulin therapy is needed when diabetic patients need to receive surgical treatment for other diseases. V. Insulin therapy is needed when type 2 diabetes is combined with acute infection, acute cardiovascular disease or other serious diseases. Sixth, early insulin therapy is recommended for patients with type 2 diabetes who have initial onset, wasting, high blood glucose, or difficult to classify. Seven, gestational diabetes, insulin therapy is needed during pregnancy. VIII. Certain special types of diabetes, such as diabetes occurring after recurrent pancreatitis, also require insulin therapy.