In addition, patients will have demonstrated evidence of either an abnormal methacholine challenge or reversible airway obstruction. An abnormal methacholine challenge will be defined as a decrease in FEV(1) of at least 20% at a PD(20) dose less than 240 micrograms. Reversible airway obstruction will be defined as an improvement of at least 12% and 200 cc in either the FEV(1) or FVC folowing bronchodilator treatment. Methacholine challenge testing will not be performed if the subject has a history of allergy to methoacholine. Result of testing performed by the subject's primary care provider may be accepted as evidence of reversible airflow obstruction.