LAUSR

Introduction Acute bronchitis is a self-limiting infection of the large airways; cough is the primary symptom, usually lasting for about 3 weeks. Annually, approximately 5% of adults develop acute bronchitis, and its economic burden is substantial. There are also problems of antibiotic abuse in public health systems and symptomatic therapies are commonly prescribed, for which there is insufficient supporting evidence. GHX02 contains four herbs originating from gwaruhaengryeon-hwan, which has been used in the treatment of patients with acute bronchitis in Korea. The objective is to compare the GHX02 and placebo in terms of efficacy and safety, and to determine the appropriate dosage. Methods and analysis We planned a phase II, multicentre, dose-finding, double-blind, randomised placebo-controlled trial of two different doses of GHX02 compared with placebo. A total of 150 patients, aged 19–75 years, with a Bronchitis Severity Score (BSS) ≥5 due to acute bronchitis starting within 2 weeks of study enrolment will be recruited from three university-affiliated hospitals across Korea. Participants will be stratified into three patterns using the Korean Standard Tool of Pattern Identifications of Cough and Sputum and randomly assigned to either a high-dose GHX02 group (1920 mg/day), standard-dose GHX02 group (960 mg/day) or placebo group according to a 1:1:1 allocation ratio. Patients will take medications three times daily for 7 days, with two visiting days. The primary outcome measure is a change in BSS from day 0 to day 7. The secondary outcomes are the Questionnaire of Clinical Symptoms of Cough and Sputum, Leicester Cough Questionnaire, frequency of coughing fits, Integrative Medicine Outcome Scale, Integrative Medicine Patient Satisfaction Scale and withdrawal rate of patients with exacerbation. Safety will be assessed by adverse events, vital signs and laboratory examinations. Ethics and dissemination The study has been approved by our Institutional Review Board (No. DJDSKH-17-DR-14). The trial results will be disseminated via peer-reviewed journals and the Clinical Research Information Service. Trial registration number NCT03310385; Pre-results.