 Acute bronchospasm associated with exacerbations of asthma is a common problem. Currently the mainstay of treatment is inhalation albuterol, either levalbuterol or racemic mixture, in repetitive fashion depending on the resolution of the airways obstruction. Formoterol is a long-acting 12 hours selective beta2-agonist that has a very rapid onset of bronchodilatation 3 minutes and thus similar to that produced by albuterol. Patients with acute bronchospasm could benefit from the prn use of formoterol as they would receive acute relief of their symptoms and this would last for a prolonged time period. Additionally formoterol has been reported to be 28-109 times as potent as albuterol and safe at doses of 54ug in healthy subjects and asthmatics. Racemic formoterol structurally has 2 chiral centers and thus is composed of 4 enantiomers. The RR form or arformoterol is the active bronchodilator and it is not clear what the physiologic actions of the other 3 enantiomers are. This study is the first to evaluate nebulized arformoterol solution for therapy of acute asthmatics presenting to the Emergency Department. 