- A significant minority of patients with COPD have favourable response to corticosteroid treatment. In addition, the benefit of corticosteroid treatment may be outweighed by the side-effects. Long-term administration of inhaled steroids is a safe means of treatment. However, only a few studies have addressed the role of inhaled steroids in patients with COPD, with conflicting results. Forty-four patients with stable COPD were defined as 'responders to bronchodilators' (increase in FEV1 > or = 20% following administration of beta 2-agonist) (group A), and 124 as 'non-responders to bronchodilators' (group B). All patients were randomized to receive a 6-week course of either a daily dose of 800 micrograms of inhaled budesonide or placebo, separated by 4 weeks when no medication was taken; were randomized again to receive a 6-week course of either 1600 micrograms day-1 of inhaled budesonide, or 800 micrograms day-1 of inhaled budesonide plus placebo; and were randomized once again to receive a 6-week course of either 40 mg day-1 of prednisone or placebo. All stages were performed in a double-blind cross-over design. Following administration of 800 micrograms day-1 of inhaled budesonide, there was an increase in the mean FEV1 from 1.40 +/- 0.20 to 1.92 +/- 0.22 L (P < 0.001) and a significant decrease in inhaled beta 2 agonist consumption in group A. These changes remained almost stable during the increased dose of inhaled budesonide or during prednisone treatment. The mean FEV1 did not change during the placebo period, or in group B in either treatments. Treatment with inhaled steroids improved spirometry data and inhaled beta 2-agonist consumption in about one-quarter of patients with stable COPD, and this rate increased to about three-quarters in patients who responded to beta 2-agonist inhalation. There was no additional benefit in using a higher dose of inhaled budesonide or prednisone.