Trial of Montelukast for Treatment of Acute Bronchiolitis

Inclusion Criteria: * Male or female infants aged 3 to 12 months of age * Diagnosis by emergency physician of bronchiolitis Exclusion Criteria: * Any previous episode, as determined by a physician, of wheezing, bronchiolitis or asthma * Any history of previous bronchodilator use prior to this illness * Treatment with corticosteroids in the 14 days prior to the current illness * Immunosuppression * Immunodeficiency * Caregiver does not speak English * Diagnosis by the treating ED physician of croup * Diagnosis by the treating ED physician of pneumonia * Caregiver does not have access to a telephone