Mucous plugs and secretions in smaller bronchi may be responsible for impaired exchange of gases and abnormal compliance. Conventional therapy is often insufficient for removal of these plugs and secretions, especially in patients treated with mechanical ventilation. Therefore, pulmonary lavage with 237 +/- 6 ml of physiologic saline solution infused through the flexible fiberoptic bronchoscope in patients with respiratory failure was accomplished on 43 occasions to evaluate the therapeutic benefit of this procedure on oxygenation and compliance. Eighty-one percent (35) of the 43 lavages were associated with a significant increase of the ratio of arterial to alveolar oxygen pressures (PaO2/PAO2) (11 +/- 1) hours after lavage; 63% (27) of the 43 lavages were associated with a significant increase in effective static compliance (Cst) at 8 (+/- 1) hours after lavage. There were no persistent complications other than transient decreases in PaO2/PAO2 and effective Cst soon after lavage. The results suggest that this procedure is a useful therapeutic method in selected patients with respiratory failure.