We have investigated whether IL-8 is present in airway secretions from patients with asthma and chronic obstructive pulmonary disease (COPD) to obtain information on its possible role in airway inflammation in obstructive airways disease. In the bronchoalveolar lavage fluid (BALF) from 11 clinically stable patients with asthma the levels of IL-8 were increased compared to 10 healthy subjects (median: controls 21.5 pg/ml, asthma 244 pg/ml: p < 0.005). In the patients with asthma the levels of IL-8 correlated with the percentage neutrophils in the BALF (r = 0.81; p < 0.001) and with a parameter of the permeability of the respiratory membrane, the quotient (alpha 2-macroglobulin in BALF)/(alpha 2-macroglobulin in serum) (r = 0.66; p < 0.025). In the sputum sol phase of 9 patients with symptomatic asthma the levels of IL-8 were lower than in 9 patients with COPD (asthma: 6.4 ng/ml; COPD: 16.3 ng/ml; p < 0.02) and significantly correlated with those of neutrophilic myeloperoxidase (MPO; r = 0.85; p < 0.005). The increased levels of IL-8 in the airway secretions from both patients with asthma and COPD may be markers of an ongoing inflammatory process, which is more pronounced in patients with COPD. In patients with asthma the strong correlation between the levels of IL-8 and the percentage neutrophils and/or the levels of MPO points to a role of IL-8 in the recruitment and activation of neutrophils in the airway lumen.