Reduced immunoglobulin A can be seen in recurrent respiratory infections, immunodeficiency diseases, hyperthyroidism, etc. It is recommended to consult the doctor and take antibiotics, stavudine, methimazole and other treatments as prescribed by the doctor. 1. Repeated respiratory infections: mainly in children, can be prescribed antibiotics anti-infective treatment, at the same time can be supplemented with nebulization can effectively reduce the cough, wheezing and other symptoms. 2. Immunodeficiency diseases: primary is mainly to prevent infection, can follow the doctor’s advice to use immunoglobulin and other alternative treatments, or hematopoietic stem cell transplantation; for secondary can follow the doctor’s advice to take stavudine and other antiviral treatment. 3. Hyperthyroidism: oral methimazole, methylthiouracil and other antithyroid drugs can be taken as prescribed by the doctor, and propranolol can also be taken to control clinical symptoms. If the immunoglobulin A is lowered, the patient should consult the rheumatology and hematology departments in a timely manner to clarify the cause of the disease, and then choose the appropriate medication or other treatments under the judgment of a professional physician.