Although lung function is grossly normal in patients with primary pulmonary hypertension (PPH), mild-to-moderate peripheral airflow obstruction can be found in the majority of patients with this disease. Therefore, beta2-agonists may affect pulmonary function, blood gases and haemodynamics in patients with PPH. Pulmonary function testing, blood gas measurements and right heart catheterisation was performed in 22 patients with PPH and the acute effects of inhaled salbutamol (0.2 mg) were measured. Salbutamol caused an increase in the forced expiratory volume in one second (FEV1) from 2446+/-704 to 2550+/-776 mL. The mean expiratory flow at 50% of the vital capacity (MEF50) rose from 58+/-17 to 66+/-21% pred. The pulmonary artery pressures remained unchanged after inhalation of salbutamol, but the cardiac output increased significantly from 3.9+/-1.4 to 4.2+/-1.4 L x min(-1) accompanied by significant increases in stroke volume and mixed venous oxygen saturation as well as a significant decrease in pulmonary vascular resistance. The arterial oxygen tension rose from 9+/-2.4 kPa (68+/-18 mmHg) at baseline to 9.7+/-2.8 kPa (73+/-21 mmHg) after inhalation of salbutamol, the alveolo-arterial oxygen gradient values improved from 6+/-2.5 kPa (45+/-19 mmHg) to 5.1+/-2.9 kPa (38+/-22 mmHg), respectively. Inhaled salbutamol has beneficial acute effects on pulmonary function, blood gases and haemodynamics in patients with primary pulmonary hypertension.