 The pilot study will be a multi-centre, randomized, placebo controlled, pilot trial. If outpatients with chronic pulmonary disease at the Firestone Institute for Respiratory Health in Hamilton and at the respirology clinics of the Foothills Medical Centre in Calgary develop influenza-like illness when influenza is known to be continuously circulating, they will be assessed at the clinics and if they meet eligibility criteria will be randomized to oseltamivir or placebo and followed prospectively. We will test for influenza by RT-PCR however acute detection of influenza will not be a criterion for entry into the trial. 