Clinicians have generally avoided prescribing corticosteroids for active infection because of their known immunosuppressive effects and concern about long-term complications. We conducted a review of the published randomized, double-blind trials comparing corticosteroids and placebo in infections. Except in some trials of viral infections, sore throat, and cerebral cysticercosis, all patients also received active antimicrobial agents in addition to placebo or corticosteroids. For patients with bacterial meningitis, tuberculous meningitis, tuberculous pericarditis, severe typhoid fever, tetanus, or pneumocystis pneumonia with moderate to severe hypoxemia, treatment with corticosteroids improved patient survival (group 1 infections). For patients with bacterial arthritis, corticosteroids were also beneficial and reduced long-term disability (group 2 infections). For about a dozen other infections, corticosteroids significantly relieved symptoms (group 3 infections), and clinicians should consider using them if symptoms are substantial. Corticosteroids were harmful in 2 infections, viral hepatitis and cerebral malaria (group 5 infections). We conclude that corticosteroids are beneficial and safe for a wide variety of infections, although courses longer than 3 weeks should be withheld from patients with concomitant human immunodeficiency virus infection and low CD4 counts.