Oral quinolones such as ciprofloxacin are promising agents in the treatment of serious bronchopulmonary infections due to susceptible gram-negative micro-organisms such as Haemophilus influenzae, Branhamella catarrhalis, Klebsiella pneumoniae and even Pseudomonas aeruginosa. Their moderative activity against Streptococcus pneumoniae may limit the use of these agents in the treatment of acute exacerbations of chronic bronchitis and in the empiric management of community-acquired bacterial pneumonia. Further prospectively designed studies are needed to address this issue. The ability of quinolones to effectively penetrate bronchial mucosa and to be concentrated within macrophages may afford additional advantage to these agents. They should not be used as a sole agent in the treatment of aspiration pneumonia nor anaerobic pleuropulmonary disease. Quinolones are very active in experimental models of Legionnaire's disease and deserve further clinical study. Ciprofloxacin is a promising alternative to standard parenteral drugs in the management of Pseudomonas aeruginosa infections in adults with cystic fibrosis. The potential for drug interactions with theophylline must be kept in mind for patients on both of these drugs.