Sputum cell-counts were studied in 7 non-smokers with corticosteroid-responsive chronic cough productive of sputum and 8 smokers with a clinical diagnosis of chronic bronchitis, all of whom had normal lung function tests and methacholine airway responsiveness, and in 10 non-smokers with asthma, examined during an exacerbation. Sputum from asthmatic patients and subjects with corticosteroid-responsive cough contained eosinophils and metachromatic cells. Macrophages were by far the dominant cell type in sputum from subjects with chronic bronchitis. Airway inflammation with eosinophils and metachromatic cells is not always accompanied by increased airway responsiveness, and current definitions of obstructive airways disease may need to be revised.