Acute exacerbations of chronic bronchitis are one of the major public health challenges. New data suggest that they will remain so for many years. Although the role of bacteria in the initiation and maintenance of bronchial inflammation, both during and between exacerbations, is well recognized, studies of the longterm effects of therapy are few and inadequate, and the nature of the relationship with disease progression is largely unknown. Data are beginning to emerge that firmly link bacterial inflammation and progressive disease with physiological and functional disability. Methods are being developed to provide integrated, uncomplicated and reproducible assessments of health-related quality of life. These may prove fundamental to the proper investigation of new treatment modalities. Among the newer antibacterial agents, fluoroquinolones have received most investigative attention, regrettably usually without providing clinical confirmation of their obvious superiority in vitro and of their pharmacokinetic and related pharmacodynamic properties. New trial designs need to address an integrated outcome analysis, with the assessment of long-term benefit and pharmaco-economic monitoring. More antibacterial agents are available at the millennium than ever before. After 50 years, it would be preferable if we knew a little more about their role in this complex disease. Curr Opin Infect Dis 13:171-176. (C) 2000 Lippincott Williams & Wilkins.