Quantitative cell counts in sputum provide a reliable method to assess bronchitis. Sputum can be safely induced with hypertonic saline even in patients with moderate and severe COPD. Similarly to asthma (7), the presence of eosinophils in sputum is a predictor of short-term response in forced expiratory volume at one second (FEV1) and quality of life to inhaled (8) and oral corticosteroids (9). A single study has demonstrated that normalizing eosinophils in sputum in patients with COPD reduces severe exacerbations and hospitalizations by approximately 60% (10). The relative risk reduction in this study is greater than that demonstrated by any study conducted so far in COPD. Long-term studies have not been conducted.