Excessive mucus sputum production and acute exacerbation of pulmonary symptoms are the main features of bronchiectasis. Inhaled osmotic agents may increase mucociliary ciliary clearance of the airways in such patients, but there have been few previous long-term clinical trials in this regard. To investigate the effect of inhaled mannitol on the frequency of acute exacerbations in patients with non-cystic fibrosis (CF) bronchiectasis, Dr. Bilton et al. from the Department of Respiratory Medicine at the Royal Brompton Hospital conducted a study suggesting that 12 months of inhaled mannitol treatment did not reduce the frequency of acute exacerbations in patients with bronchiectasis, but prolonged the time to the first acute exacerbation after treatment and improved their Quality of life. The article was published online in the September 21, 2014 issue of Thorax. The study was a randomized, controlled clinical trial. Patients with non-CF bronchiectasis who had a history of chronic heavy sputum and ≥2 acute exacerbations of pulmonary symptoms in the past 12 months were randomized 1:1 to receive 400 mg twice daily (treatment group) or 50 mg (control group) of inhaled mannitol in 2 separate groups. Mannitol was administered as a 3-micron diameter dry powder formulation for 52 weeks. The primary study endpoint was the effect of inhaled mannitol on the frequency of acute exacerbations of bronchiectasis; secondary study endpoints included time to first acute exacerbation and its duration, antibiotic use, and patient scores on the St. George’s Respiratory Questionnaire (SGRQ) and quality of life (QOL). A total of 461 patients were enrolled in the study, of which 233 and 228 were randomized to the treatment and control groups, respectively. These patients were aged 18-85 years, had a baseline FEV1 between 40% and 85% of predicted values, and a baseline SGRQ score ≥30. Baseline demographic characteristics were similar in both groups. The main findings of the study were that inhaled mannitol did not significantly reduce the frequency of acute exacerbations of bronchiectasis in the subjects. However, it prolonged the time to the first acute exacerbation after treatment. In addition, there was a significant improvement in SGRQ scores in the treatment group compared to the control group. The incidence of adverse events was essentially similar in both groups of subjects. The results of the study showed that 12 months of mannitol inhalation therapy (400 mg twice a day) did not significantly reduce the frequency of acute exacerbations in patients with bronchiectasis, but significantly prolonged the time to first acute exacerbation after treatment and significantly improved the quality of life of the patients. In addition, mannitol inhalation therapy, has a good safety and tolerability profile. The study showed that 12 months of mannitol inhalation therapy did not reduce the frequency of acute exacerbations in patients with bronchiectasis, but prolonged the time to the first acute exacerbation after treatment and improved their quality of life.