We hypothesize that hydrocortisone infusion in severe community-acquired pneumonia attenuates systemic inflammation and leads to earlier resolution of pneumonia and a reduction in sepsis-related complications. In a multicenter trial, patients admitted to the Intensive Care Unit (ICU) with severe community-acquired pneumonia received protocol-guided antibiotic treatment and were randomly assigned to hydrocortisone infusion or placebo. Hydrocortisone was given as an intravenous 200-mg bolus followed by infusion at a rate of 10 mg/hour for 7 days. Primary end-points of the study were improvement in Pa(O(2)):FI(O(2)) (Pa(O(2)):FI(O(2)) > 300 or >/= 100 increase from study entry) and multiple organ dysfunction syndrome (MODS) score by Study Day 8 and reduction in delayed septic shock. Forty-six patients entered the study. At study entry, the hydrocortisone group had lower Pa(O(2)):FI(O(2)), and higher chest radiograph score and C-reactive protein level. By Study Day 8, treated patients had, compared with control subjects, a significant improvement in Pa(O(2)):FI(O(2)) (p = 0.002) and chest radiograph score (p < 0.0001), and a significant reduction in C-reactive protein levels (p = 0.01), MODS score (p = 0.003), and delayed septic shock (p = 0.001). Hydrocortisone treatment was associated with a significant reduction in length of hospital stay (p = 0.03) and mortality (p = 0.009).