Apparatus and methods for deactivating bronchial nerves and smooth muscle extending along a bronchial branch of a mammalian subject to treat asthma and related conditions. An electromechanical transducer (11) is inserted into the bronchus as, for example, by advancing the distal end of a catheter (10) bearing the transducer into the bronchial section to be treated. The electromechanical transducer emits unfocused mechanical vibratory energy of one or more ultrasonic frequencies so as to heat tissues throughout a relatively large target region (13) as, for example, at least about 1 cm3 encompassing the bronchus to a temperature sufficient to inactivate nerves but insufficient to cause rapid ablation or necrosis of organic tissues. The treatment can be performed without locating or focusing on individual bronchial nerves.
