This study is a phase 2, multicentre, dose-finding, double-blind, randomized placebo-controlled trial to evaluate the efficacy and safety of two different doses of GHX02, compared with placebo, for acute bronchitis. One-hundred and fifty patients will be included in this trial and randomly assigned to either a high-dose GHX02 group(1920mg/day), standard-dose GHX02 group(960mg/day), or control group(placebo) in a 1:1:1 allocation ratio. Patients will take one of the medications three times a day for 7 days, with 3 visiting days(screening, day0, day7). On the screening day, the Korean Standard Tool of Pattern Identification of Cough and Sputum, a diagnostic system that determines therapy in Traditional Korean Medicine, will be used to allocate patients into three groups of wind-heat, wind-cold or others.