Explosive coughing is usually stressed as an essential element of bronchial hygiene in patients with chronic lung disease or for prevention of pulmonary complications in the postsurgical patient. Such coughing can induce bronchial collapse, which may result in secretion retention. A method of coughing nonexplosively, the "huff" cough, has been shown to stabilize collapsible bronchial walls, thereby maintaining airway patency and facilitating expulsion of secretions from the lung. The phenomenon of stabilization has been described repeatedly for more than 25 years but has not been recognized as being clinically significant. In fact, warnings against use of the huff cough have been given in texts devoted to respiratory therapy, because it was felt that airway obstruction may be increased through such use. Our investigation has shown just the opposite. The huff cough may yield its greatest benefit to the patient with obstructive lung disease.