Inclusion Criteria:

• His/her own will to participate
• Documented chemical exposure
• Clinical, spirometric and radiological findings were compatible with BO on High Resolution Computed Tomography (HRCT)

Exclusion Criteria:

• any drug reactions during the trial
• history of sensitivity to macrolides
• diarrhea, gray stool, jaundice, eosinophilia, acute cholestatic hepatitis, pruritis, dark urine, abdominal pain, osteomatosis, depression, taste change, behavioural changes, early fatigue, odynophagia, glossitis , dizziness
• co-adminstration of: terfenadine, theophylline, carbamazepine, ergotamine, dihydroergotamine, warfarin, cisapride, digoxin, triazolam, phenytoin, steroids, any immunosuppressive, any systemic antibiotics
• using drugs that he/she cannot discontinue
• using drugs with potential interaction
• subject will to exit from the trial
• history of lobe resection of lung
• history of exacerbation in the last month prior to the beginning of trial
• continuous need to oxygen
• use of corticosteroids in last week prior to the trial beginning
• Radiographic evidence of pneumonia, active tuberculosis, lung carcinoma, or an infection that necessitated the use of an antibiotic
• exacerbating of subjects
• creatinine srum level more than normal
• increasing ALT, AST levels
• total bilirubin more twice than normal
• subjects who did not use their drugs properly