Twenty male outpatients with severe-but-stable chronic obstructive pulmonary disease handicapped by exertional dyspnoea (aged 69.7 +/- 5.68 yrs; forced expiratory volume in one second (FEV1) 1.02 +/- 0.18 L or 34.6 +/- 6.5% of the predicted value; forced vital capacity (FVC) 2.51 +/- 0.34 L; arterial oxygen tension (Pa,O2) 9.11 +/- 0.32 kPa (68.5 +/- 2.4 mmHg); arterial carbon dioxide tension (Pa,CO2) 5.20 +/- 0.23 kPa (39.1 +/- 1.7 mmHg)) completed a randomized double-blind crossover study to evaluate the effects of a 4-week regular treatment with inhaled beclomethasone dipropionate via nebulizers at a dosage of 2 mg twice daily. After active and placebo treatment, no peak expiratory flow rate variation in FEV1, FVC, rescue use of beta 2-agonists, exercise tolerance and dyspnoea was observed. In conclusion, a regular short-term treatment with nebulized beclomethasone dipropionate does not give any improvement in lung function or exercise capacity in severe-but-stable chronic obstructive pulmonary disease patients handicapped by exertional dyspnoea.