Chronic obstructive pulmonary disease (COPD) constitutes an enormous, and growing, health problem, the treatment of which has been less than satisfactory so far. COPD is a chronic inflammatory process in the airway wall of the large and peripheral airways as well as in the parenchyma. Because of this inflammation, glucocorticosteroids (steroids) have been investigated in more than 100 studies. By tradition, the forced expiratory volume in 1 s (FEV(1)) has been utilized as the main outcome parameter. More recently, exacerbation frequency and health status (quality of life) have been added as end points. Oral steroids have been demonstrated to be useful during exacerbations, although the effects are smaller than in exacerbations of asthma. In stable COPD, 10% more patients respond favorably to a 2-wk course of steroids than to placebo. The long-term effects of oral steroids have not been evaluated in randomized controlled trials. There have now been 10 studies of inhaled steroids of short duration, defined as up to 3 mo. In general, there was no effect on FEV(1). No other parameters of lung function were consistently measured. Several studies showed a small effect on some inflammatory parameters, but none of these were comparable between studies and therefore await further confirmation and elaboration. In total, eight studies evaluated inhaled steroids over a long period, i.e., at least 6 mo. Five of these have been published, and three major large-scale studies have been presented as abstracts at major meetings but not yet published in full. On the basis of these studies, there seems to be an effect of inhaled steroids during the first 3-6 mo of use, but thereafter no effect on the subsequent decline of lung function has been found. Two studies have documented a reduction in exacerbation frequency and an improvement in health status. In summary, as far as FEV(1) is concerned, there is only a short-term benefit of inhaled steroids at best. The improvements in exacerbations and health status need to be confirmed and valued, but could well be important to patients. There is an urgent need to identify those patients within the large heterogeneous group of patients with COPD who benefit from steroids. For this, it would be useful to pool data from the long-term studies. Postma DS, Kerstjens HAM. Are inhaled glucocorticosteroids effective in chronic obstructive pulmonary disease?