Systemic corticosteroids have been used in the treatment of numerous medical conditions for approximately 50 years. Short-acting products such as hydrocortisone are the least potent. Prednisone and methylprednisolone, which are intermediate-acting products, are four to five times more potent than hydrocortisone. Dexamethasone is a long-acting, systemic corticosteroid; its potency is about 25 times greater than the short-acting products. Corticosteroids reduce the need for hospitalization in patients with croup and decrease morbidity and the incidence of respiratory failure in the treatment of patients with AIDS who have Pneumocystis carinii pneumonia. Other often overlooked indications for corticosteroids are the treatment of hyperthyroid states, including thyroid storm, subacute thyroiditis and ophthalmopathy of Graves' disease. Systemic steroids can be used as adjuvant analgesics in the treatment of neuropathic and cancer-related pain. They may also decrease mortality in patients with severe alcoholic hepatitis and concomitant encephalopathy. Corticosteroids can reduce complications in patients with meningitis caused by Haemophilus influenzae or Mycobacterium tuberculosis.