The Effects of Long Term Inhalation of Hypertonic Saline in Subjects With Cystic Fibrosis

Inclusion Criteria: * Confirmed diagnosis of CF (sweat tests/genotype) * The subject, or their legal guardian for children under 18 years old, must provide written informed consent. * The subject must be in stable clinical condition at the time of and for a period of 14 days prior to their recruitment into the study. * Age \> 6 years old * FEV1 \> 40% predicted for height, age and gender * Proven or anticipated compliance with therapy or study protocol * Regular attendee at a Cystic Fibrosis Clinic (\> 2 visits per year) * Able to reproducibly perform lung function tests (spirometry) * Relatively stable nutritional status (\< 2 kg weight loss in last 6 months and \< 5 kg weight loss in last year) * Known to have "normal" (for CF subject) laboratory tests - haematology, biochemistry, immunology, coagulation, etc. Exclusion Criteria: * Requiring home oxygen (pO2 \<55mmHg or pCO2 \>50mmHg) or assisted ventilation. * Considered "terminally ill" or listed for transplantation (either lung or liver). Subjects that are listed for transplant after being enrolled in the trial are eligible to continue in the trial. * Subjects colonised with Burkholderia cepacia. However, if a subject becomes colonised with B. cepacia during the trial, they should continue in the trial. Subjects should be considered to be B. cepacia positive if they have had even a single lifetime isolate. In these subjects, spirometry should be measured on a dedicated spirometer. * Cigarette smoker. * Exposure to investigational drugs within the past 30 days. * Major haemoptysis (\> 60 mL in a single episode) within the last twelve months. * Concurrent illnesses eg. cor pulmonale, clinically significant liver disease (portal hypertension, varices). * Known allergy to quinine sulphate, Glucose 6-phosphate dehydrogenase deficiency. * Immune thrombocytopaenic purpura. * Pregnant or lactating females. * At risk females unwilling to use appropriate contraception to prevent pregnancy for the duration of their enrolment in the study.