The normal value of eosinophil ratio is between 0.5% and 5%, while low eosinophil ratio means less than 0.5%, the significance of which includes physiological factors such as circadian cycle fluctuation and pathological factors such as after major surgery. 1. Physiological factors: The number of eosinophils fluctuates periodically during the day and night, with a decrease in the number in the early morning and an increase in the number at midnight. The cause of this change is mostly related to the fluctuation in the amount of glucocorticoids released from the adrenal cortex. Usually no treatment is needed. 2. Pathological factors: When the patients are in the state of stress, such as after major surgery, burns and long-term application of adrenocorticotropic hormone, the eosinophil count is often low. Usually, it is necessary to combine clinical symptoms, signs and other auxiliary examinations for treatment. If you have low eosinophil rate in daily life, you can go to regular hospitals to avoid delaying your condition.