Buspirone is an anxiolytic agent that appears to have no sedative effects. The aim of this study was to assess the effects of buspirone on breathlessness and exercise tolerance in patients with chronic airway obstruction. Sixteen patients, age 56.9 +/- 17.0; forced expiratory volume in 1 s (FEV1) 1.15 +/- 0.42 l; FEV1/forced vital capacity (FVC) 50.7 +/- 15.0%; PaCO2 42.2 +/- 5.5 mm Hg; and PaO2 57.6 +/- 10 mm Hg, underwent a 6-min walking test, an incremental cycle ergometer test, an incremental treadmill walking test with self-assessment of dyspnea on Borg's scale during exercise and an assessment of respiratory drive (P 0.1), timing [inspiration time (TI)/total breathing time (Ttot)], PaO2, PaCO2, FVC, FEV1, following oral administration for 14 days of placebo or buspirone (20 mg daily) in a double-blind, cross-over randomized way. We also used the symptom check list-90-R for the assessment of subjective complaints and symptomatic behavior. A significant improvement in anxiety, depression and obsessive symptoms and complaints was noted after buspirone treatment. The P 0.1, TI/Ttot, arterial blood gases and respiratory mechanics did not change after drug treatment. There was an improvement in exercise tolerance and in the sensation of dyspnea during the buspirone period. Thus, as given in this study, oral buspirone has therapeutic potential in the treatment of dyspnea in patients with chronic lung disease.