Eosinophil percentage of 0.3 does not require treatment if there are no uncomfortable symptoms, but if it is persistently low and accompanied by discomfort, then treatment is required. 1. The normal value of eosinophil is 0.5%~5%, 0.3% suggests that the eosinophil is low. 2. Eosinophilia is mainly seen in stress (such as burns, acute infectious diseases in the extreme stage), typhoid fever, paratyphoid fever, shock and Cushing’s syndrome. It may also be seen after surgery with severe tissue trauma and after the application of adrenocorticotropic hormone or pro-adrenocorticotropic hormone. When eosinophils are low, if there are no uncomfortable symptoms do not need treatment, if persistently low with physical discomfort need to go to the hospital for a systematic examination, in order to clarify the cause of the disease, early diagnosis and early treatment.