Immunosuppressants refer to drugs that inhibit the body’s immune response, including cyclosporine, methotrexate, cyclophosphamide and so on. Immunosuppressants are often used in combination with glucocorticoids in the treatment of systemic lupus erythematosus (SLE), dermatomyositis, and pemphigus in order to enhance therapeutic efficacy, help with hormone dosage reduction, and minimize adverse effects, and can also be used alone. Organ transplant recipients require lifelong immunosuppression to prevent rejection. Adverse effects of immunosuppressive agents such as cyclosporine, methotrexate, and cyclophosphamide include gastrointestinal reactions, myelosuppression, hepatic damage, induced infections, and teratogenicity, so they should be used with caution and should be monitored regularly during administration. Immune preparations need to be taken under the guidance of a doctor, do not self-medication, so as not to cause adverse effects.