Bronchiectasis is a chronic disorder characterized by impaired mucociliary clearance and a relentless cycle of infection, inflammation and bronchial wall injury, which has a debilitating impact on the patient's quality of life and results in increased morbidity and mortality. It is a disease for which there are no currently registered therapeutic products, limited epidemiological data and no validated endpoints that have been accepted by the majority of regulatory authorities. This article reviews the evidence base for the efficacy of inhaled dry powder mannitol in patients with non-cystic fibrosis (CF) bronchiectasis. The few published papers on this topic concluded that mannitol, when inhaled as a dry powder, is a promising treatment for bronchiectasis. It is designed to hydrate the lungs and restore normal mucociliary clearance mechanisms in the lungs. Based on the available evidence, mannitol inhalation is well tolerated and improves the quality of life of patients with non-CF bronchiectasis. There is a need for well designed and adequately powered multicentre trials to establish the potential usefulness of mannitol as a treatment for non-CF bronchiectasis.