Asthma is a common chronic condition that disproportionately affects persons younger than 45 years. Asthma exacerbations can be sudden and severe, requiring treatment in the emergency department or hospitalization. Children younger than 15 years are 2-4 times more likely to have asthma as the first-listed hospital discharge diagnosis compared with those in other age groups. An estimated 12.8 million missed school days and 24.5 million lost work days due to asthma occurred in 2003. Drugs used in the treatment of acute asthma include inhaled beta(2)-agonists, oral corticosteroids, and inhaled anticholinergics. Levalbuterol was evaluated in several recent trials for treatment of asthma in the emergency department, for its effect in improving pulmonary function and on hospitalization rate. Theophylline, intravenous beta(2)-agonists, intravenous magnesium sulfate, and inhaled anesthetics have not been proven useful in the emergency management of asthma. The effectiveness of inhalation devices is dependent on age, cooperation of the patient, and technique.