BRONCHIAL ASTHMA CAN BE DIAGNOSED WHEN A PATIENT DEVELOPS THE CLINICAL MANIFESTATIONS OF BRONCHIAL REACTIVITY: wheezing, cough, tachypnea, and dyspnea. Occasionally, despite immunotherapy, bronchodilator therapy, and avoidance of the provocative factors, some asthmatic patients do not respond to treatment. Bronchial inhalation challenge, a method to test airway reactivity after inhalation of a nonspecific drug, can be used to plan and assess different modes of treatment, as well as screen for bronchial hyperreactivity in an occupational setting.