In 2002 the National Asthma Education and Prevention Program published evidence-based guidelines for the diagnosis and management of asthma, but there are some unresolved asthma-management issues that need further research. For asthmatic children inhaled corticosteroids are more beneficial than as-needed use of beta(2) agonists, long-acting beta(2) agonists, theophylline, cromolyn sodium, nedocromil, or any combination of those. Leukotriene modifiers are an alternative but not a preferred treatment; they should be considered if the medication needs to be administered orally rather than via inhalation. Cromolyn sodium and nedocromil are effective long-term asthma-control medications, but they are not as effective as inhaled corticosteroids. There is insufficient evidence to determine whether cromolyn benefits maintenance of childhood asthma. Cromolyn sodium and nedocromil are alternatives, but not preferred treatments for mild persistent asthma. Cromolyn may be useful as a preventive therapy prior to exertion or unavoidable exposure to allergens. Regular inhalation of corticosteroids controls asthma significantly better than as-needed beta(2) agonists. No studies have examined the long-term impact of regular inhaled corticosteroids on lung function in children < or= 5 years old. As monotherapy, inhaled corticosteroids are more effective than long-acting beta(2) agonists. The asthma-control benefit of inhaled corticosteroids decidedly outweighs the risks from inhaled corticosteroids. There is no high-level evidence that low-to-medium-dose inhaled corticosteroids have ocular toxicity or important effects on hypothalamic-pituitary-adrenal function in children. Antibiotic therapy has no role in asthma management unless there is a bacterial comorbidity, but further research is needed on the relationship between sinusitis and asthma exacerbation. The asthma care plan should include a written asthma action plan for the patient, but there is inadequate evidence as to whether the asthma action plan should be based on symptoms or on peak flow monitoring. There is low-level evidence that helium-oxygen mixture (heliox) may be of benefit in the first hour of an acute asthma attack but less advantageous after that first hour. Metered-dose inhalers are no more or less effective, overall, than other aerosol-delivery devices for the delivery of beta(2) agonists or inhaled corticosteroids, so the least expensive delivery method should be chosen.