Immunodeficiency usually refers to immunodeficiency diseases, which usually cannot be cured, but can be improved by boosting immunity. Immunodeficiency diseases mainly include primary immunodeficiency diseases and secondary immunodeficiency diseases. Primary immunodeficiency diseases are common in infants and young children and are mostly caused by genetic predisposition. People with primary immunodeficiencies have low immunity and are highly susceptible to serious infections. Secondary immunodeficiency diseases can be caused by infections, tumors, medications, or physical or chemical factors that cause temporary or persistent damage to the immune system, resulting in defective immune function. Immunodeficiency diseases cannot be completely cured at this time. Immunodeficiency diseases can be treated according to the specific cause and severity of the disease under the guidance of a doctor. Currently, drugs such as static injection of human immunoglobulin, injectable transfer factor and thymopeptide are used to enhance immunity, or hematopoietic stem cell transplantation is used to improve immunity. Active treatment of primary diseases and removal of physical and chemical factors causing immunodeficiency are also needed. In addition, immunodeficiency diseases require isolation for protection and infection control. It is recommended that patients with immunodeficiency diseases should go to the hospital in a timely manner, identify the cause of the disease and follow the standardized treatment prescribed by the doctor.