Study will assess the safety and effectiveness of 12 week treatment with the study medication, Bronchitol, in subjects with bronchiectasis (a lung disease where patients have trapped, and often infected, thick, sticky mucus). Past studies have shown Bronchitol inhalation may help to facilitate the clearance of mucus by altering its rheology (making it less thick and sticky), thereby enhancing the shift of stagnant mucus from the lungs. On completion of the double blind phase, subjects will have the opportunity to participate in a 52 week open label phase.