Objective To investigate the relationship between the levels of fractional exhaled NO and airway inflammation cells in cough variant asthma(CVA)and the effect of inhaled corticoids .Methods CVA patients were treated with Budesonide and Formoterol Fumarate Powder for Inhalation for 6 months .Before and after treatment ,the provocative concentration of methacholine causing a 20% fall in forced expiratory volume in one second(PC20 FEV1 )was tested ,and the levels of fractional exhaled No ,and eo‐sinophil in induced sputum were examined .Results The levels of FeNO ,the percentage of eosinophil in induced sputum were sig‐nificantly higher than control healthy subjects ,and all decreased significantly after treated with ICS/LABA ,together with elevated PC20 FEV1 .The levels of FeNO were significantly correlated with the percentage of eosinophil in induced sputum ,and also negative‐ly correlated to PC20 FEV1 .Conclusion The levels of FeNO in CVA patients were significantly higher than control healthy sub‐jects ,and correlated with the inflammation of airway ,so FeNO may be used as a biomarker to determine the control level of airway inflammation in CVA patients .