ATG is the abbreviation of anti-thymocyte globulin. ATG is an immunosuppressive agent mainly used in the treatment of patients with acute aplastic anemia, and it is also the first choice of treatment for acute aplastic anemia, especially for older patients without suitable bone marrow donors. . Prior to the application of ATG, dexamethasone 5mg is administered intravenously to prevent adverse effects. After the application of ATG, the patient will show obvious manifestations of bone marrow suppression. Such patients often need to stay in the laminar flow ward, actively prevent infection, and enhance supportive treatment, including transfusion of red blood cells and platelets, application of antibacterial drug therapy, etc. In clinical practice, ATG is often used in combination with cyclosporine and androgens for better results.