BACKGROUND: The discomfort caused by chronic cough, that is persistent for more than 3 weeks, causes a number of patients to seek medical attention. However, the underlying disorder often remains undetermined despite thorough examinations, and is considered to be idiopathic. This study compared the efficacy of inhaled corticosteroid with conventional cough suppressants on chronic idiopathic cough. METHODS: Eligible patients with chronic idiopathic cough were randomly assigned to either the inhaled fluticasone group or the codeine plus levodropropizine oral administration group. The subjects in each group took their planned medication for 2 weeks. After the trial, comparative analyses of outcomes were performed in terms of the remnant cough (%) at the end of treatment, drug compliance, and adverse drug events. RESULTS: Seventy-seven patients were enrolled in this randomized trial; 38 to the inhaled fluticasone group and 39 to the codeine plus levodropropizine group. The remnant cough was 41.0+/-35.8% in the inhaled fluticasone group, and 32.4+/-32.0% in the codeine+levodropropizine group (p=0.288). Drug compliance was 95.4+/-7.4% and 81.8+/-18.6% in the inhaled fluticasone and the codeine+levodropropizine group, respectively (p<0.001). Nine patients had adverse drug events in the codeine+levodropropizine group compared to one in the inhaled fluticasone group (p<0.001). CONCLUSION: Short-term inhaled corticosteroid is not inferior to conventional antitussive agents in controlling chronic idiopathic cough without significant adverse events.