RESULTS: Data from seven female and two male patients were used for analysis, age from 66 to 80 years old. 4 patients had dry cough and 5 patients had productive cough. Auscultation showed velcro sound in all patients. Four patients showed abnormal lung function, and eight patients showed decreased diffusion function. High-resolution computed tomography revealed ground glass opacity or reticulation lesion in lower lobe. The combination of clinical features, such chronic cough and velcro sound in auscultation, CT scan and laboratory tests resultscan confirm the diagnosis of IIP. All patients failed to antibiotics treatment. Their cough was improved following glucorticosteroids treatment.