Progress has been made in the treatment for patients with croup and bronchiolitis in the past decade. By intervening with pharmacologic agents, a better outcome has been documented in children with these diseases. A lower probability of hospital admission means that fewer health care dollars need to be expended in this area. The present state of evidence substantiates the following. Bronchiolitis . Nebulized albuterol causes significant short-term improvement in clinical scores in bronchiolitic children, but there is no evidence that it reduces admission rates or decreases length of hospitalization. . Nebulized epinephrine results in significant improvement in clinical scores and airway resistance in children hospitalized with bronchiolitis and in the emergency department causes acute improvement in oxygenation, decreases length of time in the emergency department and admission rate to hospital. . There is no evidence to support the use of dexamethasone or other glucocorticosteroids for infants hospitalized with bronchiolitis. Croup . Nebulized budesonide or oral dexamethasone results in acute clinical improvement in outpatients with mild to moderate croup, reducing the need for hospitalization. . A combination of nebulized budesonide and oral dexamethasone may provide the best clinical outcome, although further evidence is needed to substantiate this . The required dose of oral dexamethasone may range from 0.15 mg/kg to 0.6 mg/kg for best clinical outcome. . Use of racemic epinephrine or L-epinephrine in the emergency department, especially when used concomitantly with glucocorticoids, does not require automatic hospital admission; a 3-hour observation period in the emergency department may suffice. . Use of intramuscular dexamethasone is difficult to justify in patients with croup who are able to ingest oral medications. Future studies need to examine dosing of glucocorticoids for inpatients with croup. In addition, an important question remains as to whether very mild croup patients (those with no evidence of respiratory distress) might benefit from glucocorticoids administered in the physician's office or the emergency department.