In this issue of CHEST (see page 605), Kahrilas et al1 report the results of their systematic review of clinical trials reporting cough response to antireflux therapy. They identified nine randomized, controlled studies that treated patients with acid suppression. Eight of the nine trials used proton pump inhibitors (PPIs) (daily or bid for 8-16 weeks); one trial used ranitidine (150 mg daily for 8 weeks). The authors report that there was significant study variability in methodology and measured outcome. Although they could not definitively state that acid-suppression therapy benefits patients with chronic cough, they could not dismiss that possibility. Importantly, they found that the therapeutic gain was in favor of PPI therapy if patients had pathologic esophageal acid exposure (range, 12.5% to 35.8%) than if they had normal esophageal acid exposure (range, 0.0% to 8.6%). The authors conclude that “rigorous patient selection is necessary to identify patient populations likely to be responsive” to acid-suppression therapy.