Objective To evaluate the effect of inhalation of furosemide on lung function and airway hyperresponsiveness in asthmatic patients.Methods By double blind randomized controlled trial,the effect of inhalation of furosemide (20mg twice daily) on the lung function and airway hyperresponsiveness in the asthmatics was studied.Results Most of lung function tests of the observation group improved 10 days after inhalation therapy.The improvement of VC,FVC and FEV 1 was significant statistically.There was also slight improvement of lung function in the control group,but not statistically significant.but it was decreaded slass.Conclusion Asthma can be relieved by inhalation of furosemide.