This article has highlighted several new concepts in the pathogenesis of bronchiectasis and proposed a hypothesis that could explain the deterioration seen in some of the patients. Modification of our current antibiotic policy has been shown to be beneficial in both the short and long term. The results of recent studies would suggest that patients with purulent sputum benefit from antibiotic therapy whether this represents an acute exacerbation or the usual clinical state. Exacerbations respond well to broad-spectrum antibiotics effective against H. influenzae and S. pneumoniae in conventional doses. However failure to respond, particularly when the usual secretions are purulent, often indicates that dosage is inadequate and a trial of a higher dosage of an agent such as amoxicillin may well prove effective. Treatment of patients who are also penicillin sensitive needs to be clarified, although no orally effective alternative has yet been identified. Relapse is rapid in patients whose usual secretions are purulent, and long-term therapy improves well-being and several biochemical indices of important pathogenic mechanisms. However, as we understand the reasons for bacterial colonization and persistence better, it should prove possible to modify other mechanisms therapeutically, thus negating the need for long-term antibiotic therapy and the associated potential risks of resistance.