Low lymphocytes are commonly associated with immunodeficiency and the use of adrenocorticotropic hormones, while low eosinophils are commonly associated with typhoid fever, paratyphoid fever, and long-term use of adrenocorticotropic hormones. Therefore, if lymphocytes and eosinophils are low at the same time, it is usually considered to be related to long-term application of adrenocorticotropic hormone or infection with typhoid or paratyphoid fever in immunodeficient patients. 1. Long-term application of adrenocorticotropic hormone: Since adrenocorticotropic hormone can inhibit hematopoiesis or invade blood cells, it can cause low lymphocytes and eosinophils. When both are clinically low, it is recommended to ask the patient’s medication, if long-term use of adrenocorticotropic hormones, such as dexamethasone, etc., if necessary, can stop the drug and recheck the blood routine; 2, immunodeficient patients infected with typhoid or paratyphoid fever: if the patient himself suffers from immunodeficiency diseases, such as AIDS, due to the immunodeficiency itself inhibits hematopoiesis, causing low self lymphocytes. If the patient is infected with typhoid or paratyphoid fever, as typhoid and paratyphoid fever can also damage blood cells, which can cause low eosinophils and thus low lymphocytes and eosinophils at the same time. In conclusion, if a patient has low lymphocytes and low eosinophils, it is recommended that he or she be seen in a hospital and that a comprehensive analysis be made, taking into account the patient’s clinical symptoms, medication history, and test results, rather than relying on this test alone to confirm the diagnosis.