AIM:To compare two different daily doses oflansoprazole given for 12 weeks and to assess the roleof gastrointestinal (GI) investigations as criteria forselecting patients.METHODS:Out of 45 patients referred for unexplainedchronic persistent cough,36 had at least one of theGI investigations (endoscopy,24-h esophageal pH-metry and a 4-week trial of proton pump inhibitor (PPI)therapy) positive and were randomly assigned to receiveeither 30 mg lansoprazole o.d.or 30 mg lansoprazoleb.i.d,for 12 weeks.Symptoms were evaluated atbaseline (visit 1) after the PPI test (visit 2) and after the12-week lansoprazole treatment period (visit 3).RESULTS:Thirty-five patients completed the studyprotocol.Twenty-one patients (60.0%) reportedcomplete relief from their cough with no differencebetween the two treatment groups (58.8% and 61.1%had no cough in 30 mg lansoprazole and 60 mglansoprazole groups,respectively).More than 80% ofthe patients who had complete relief from their cough atthe end of the treatment showed a positive response tothe PPI test.CONCLUSION:Twelve weeks of lansoprazole treatmenteven at a standard daily dose,is effective in patientswith chronic persistent cough.A positive response to aninitial PPI test seems to be the best criterion for selectingpatients who respond to therapy. AIM: To compare two different daily doses oflansoprazole given for 12 weeks and to assess the roleof gastrointestinal (GI) investigations as criteria forselecting patients. METHODS: Out of 45 patients referred for unexplained chronic beats, 36 had at least one of theG investigations (endoscopy , 24-h esophageal pH-metry and a 4-week trial of proton pump inhibitor (PPI) therapy) positive and were randomly assigned to receive elicited 30 mg lansoprazole odor 30 mg lansoprazoleb.id for 12 weeks. Symptoms were evaluated at baseline ( visit 1) after the PPI test (visit 2) and after the 12-week lansoprazole treatment period (visit 3) .RESULTS: Thirty-five patients completed the studyprotocol.Twenty-one patients (60.0%) reportedcomplete relief from their cough with no differencebetween the two treatment groups (58.8% and 61.1% had no cough in 30 mg lansoprazole and 60 mg lansoprazole groups, respectively) .More than 80% of the patients who had complete relief from their cough atthe end of the treatm ent showed a positive response tothe PPI test. CONCLUSION: Twelve weeks of lansoprazole treatmenteven at a standard daily dose, is effective in patients with chronic persistent cough. A positive response to an initial PPI test seems to be the best criterion for selecting patients who respond to therapy.