A selected group of patients with cystic fibrosis (CF) has been given a series of injections with a multivalent Pseudomonas vaccine. These patients are now being followed to measure their responses in terms of clinical status, antibody levels in serum and bronchial secretions and pulmonary colonization with Pseudomonas. Recurrent pneumothorax has become a significant clinical problem with the older patients with CF. Since surgical intervention and obliteration of the pleural space carries a significant degree of risk, we have sought to achieve obliteration of the pleural space by non- surgical means. Selected patients with recurrent pneumothorax are treated with intrapleural instillation of quinacrine hydrochloride. To date this seems to be an effective and safe method for the prevention of recurrent pneumothorax. Pulmonary toilet is one of the most significant pulmonary problems in CF. We are investigating methods of bronchial lavage with the use of the fiberoptic bronchoscope via a transnasal approach. Selected patients undergo transnasal fiberoptic bronchoscopy with installation of normal saline into the bronchial tree. In preliminary studies this seems to result in significant removal of pulmonary secretions and clinical improvement. Arterial blood gases and detailed pulmonary function studies are performed before and after each procedure. The rate of mucociliary ariway clearance in patients with cystic fibrosis is being studied by a newly developed direct technique involving the use of the fiberoptic bronchoscope and cinematography. The effects of pharmacological agents from the mucociliary airway clearance in patients with CF is also being evaluated as a possible therapeutic method.