Study design: This was a single-centre, randomized, double-blind, placebo controlled, parallel group trial with three visits at the same time of the day at intervals of two weeks. At a screening visit a detailed structured history, physical examination, record of previous or current Canadian medications and previous investigation, spirometry, methacholine inhalation test, allergy skin prick tests, and chest x-ray (if not performed in the previous three months) were performed. At the first visit, patients who met the inclusion criteria were consecutively enrolled and randomized to receive budesonide Turbuhaler (Astra Pharma Canada Inc, Mississauga, Ontario) 400 |ig/inhalation twice daily or identical placebo Turbuhaler (one inhalation twice daily) for two weeks. The randomization sequence was generated by computer off-site, was concealed from the investigators and administered by a research nurse. Patients completed a questionnaire of cough frequency and characteristics, graded cough discomfort on a visual analogue scale (VAS), and underwent sputum induction and blood collection.