The Third International Symposium on Cough focused on acute and chronic cough, both clinical and basic science. Cough is a defensive and clearing mechanism, and can cause discomfort and nuisance; it is also an important symptom of many chronic airway diseases. In this Symposium, several issues concerning the relationship of cough to disease processes, different types of cough, and the concept of idiopathic cough will be discussed. Characterization of cough receptor(s) and identification of peripheral and central mechanisms for cough sensitization are current areas of investigation for delineating the cause of chronic cough. Peripheral mechanisms may be most important for acute cough such as after viral infections. The role of pathological changes at the level of the airway mucosa and of cortical pathways will be reviewed. Finally, therapeutic inhibition of the cough reflex remains an area of active research.