Elborn et al 1 have attempted to address the important question of whether it is better to treat patients with cystic fibrosis (CF) who have chronic Pseudomonas aeruginosa infection with intravenous antibiotics on the basis of symptoms or to treat them electively, and found no significant difference between their groups. They chose a particularly unwell subgroup of the CF population to study, and one might expect a policy of increasing from three symptomatic to four elective courses of intravenous antibiotics to make the least difference in such patients. We believe that patients who require 2–4 courses of intravenous antibiotics per year anyway are not those for whom this question of treatment is most pressing …