The common causes of low eosinophils are physiologic and pathologic. 1. Physiological reasons: eosinophil reduction in peripheral blood is often caused by mental stimulation, cold, labor, hunger, etc. It is usually higher in the daytime and lower at night, with obvious diurnal fluctuations, and can be restored to normal by itself. 2. Pathologic causes: the most common is infection, such as typhoid fever infection or paratyphoid fever infection in the early stage. In addition, there are burns and after major surgery, as well as leukemia, aplastic anemia and other blood system diseases, as well as long-term use of adrenal glucocorticoids and other reasons. Low eosinophil clinical significance is generally not significant, need to be analyzed in conjunction with the symptoms, it is recommended that the patient go to the hospital in a timely manner, to identify the cause of the disease, under the guidance of the doctor to give the corresponding treatment.