Oral corticosteroids are powerful relatively nonspecific antiinflammatory agents with a range of well-characterized side effects. There is good evidence to show that they accelerate the rate of resolution of exacerbations of COPD and relapse is less likely if patients receive these drugs. Maintenance therapy with oral preparations is associated with worse mortality and skeletal muscle myopathy is a particular problem. Corticosteroids have little effect on biopsy proven inflammation or its surrogates in COPD and did not change the rate of decline of FEV (1) over a range of spirometric disease severity in a number of trials each lasting 3 years. However, meta-analysis of the data suggests that a small effect (up to 10 ml /year) might be present. There is more consistent evidence for an effect on postbronchodilator FEV (1) with both fluticasone propionate and budesonide. In patients with a postbronchodilator FEV (1) < 50% predicted where self-reported exacerbations become more common, inhaled corticosteroids can reduce the number of attacks. This effect is the major factor accounting for the reduction in deterioration in health status seen in patients who receive inhaled corticosteroids. Inhaled corticosteroids are much safer than oral therapy, although they do have a predictably higher incidence of candidiasis and hoarseness of the voice. Skin bruising is seen in patients with better lung function who use these drugs. Triamcinolone use is associated with reduction in bone density but this was not seen with budesonide. Combining an inhaled corticosteroid and a long-acting beta-agonist in the same inhaler increases the efficacy of the latte drug in COPD patients, with a significantly larger improvement in FEV (1), a larger reduction in reported breathlessness, and a reduction in exacerbation numbers in those with severe disease where beta-agonists appear to be less effective. Inhaled corticosteroids are not suitable for monotherapy in COPD but can be helpfully combined with an inhaled bronchodilator in patients with symptomatic disease.