Abstract: Abstract: Objective To explore the expression and clinical significance of serum eosinophil cationic protein (ECP) and peripheral blood eosinophile count(PBEC) in wheezing children under 5 years old. Methods Children with recurrent wheezing under 5 years old had been randomly enrolled including 43 boys and 10 girls. They were divided into 2 groups : wheezing group Ⅰ with atopic high risks （n=27）、wheezing group Ⅱ without atopic high risks （n=26）.Children without infectious diseases such as hernia and renal calculus had been enrolled randomly as normal control group（n=20）inculding 11boys and 9girls.After taking 3ml venous blood and centrifuging, the level ECPof in the serum was measured with PharmaciaUniCAP system, PBEC measurement was performed in the meantime by means of eosine staining . Results The serum levels of ECPand PBEC in wheezing groupⅠ were significantly higher than those of wheezing group Ⅱand the control group, the difference was statistically significant (P <0.05, P <0.01), while wheezing group Ⅱ group and the control group had no significant difference (P > 0.05); serum ECPand PBEC have positive correlation (r=0.786，P＜0.01). Conclusion The level serum of ECPand PBEC have an intimate relation with atopic high risks .The detections of them can be used as laboratory index to distinguish wheezing children with different clinical phenotype, early intervention and treatment should be given to the children who have a tendency to persistent wheezing.

Key words: children, wheezing, eosinophil cationic protein, eosinophile