Cough often lasts for over one year and is associated with airway inflammation. The effect of inhaled corticosteroids on symptom severity and inflammatory mediator levels in these patients is unknown. The main objective of the thesis was to determine whether inhaled corticosteroids reduce cough severity and sputum mediator concentrations in patients with chronic persistent cough. We also endeavoured to find non-invasive markers of inflammation that would predict corticosteroid responsiveness. The secondary aims of the thesis were to evaluate the role of neurotrophins in chronic cough, quality of life in cough and the effect of specific treatment, extrathoracic airway hyperreactivity and the value of clinical history in predicting the final diagnosis of cough.