The aim of the present study is to evaluate the efficacy and safety of Maekmoondong-tang on post-operative cough in patients with lung cancer. A randomized, double-blind, placebo-controlled trial will be conducted.

Inclusion Criteria:

• Adults over 20 years old.
• Patients undergone segmentectomy or lobectomy for lung cancer within 1 month
• Patients who do not or poorly respond to one week administration of common antitussive agents.
• Eastern Cooperative Oncology Group(ECOG) 0 to 2
• Participant is willing and able to give informed consent for participation in the study

Exclusion Criteria:

• Patients undergoing adjuvant chemotherapy.
• Patients who have been diagnosed with acute respiratory disease within 1 month.
• Patients who have been diagnosed with bronchial asthma or bronchiectasis within 1 year
• Patients taking Angiotensin Converting Enzyme Inhibitor
• Patients with pseudoaldosteronism.
• Participants who have known prior hypersensitivity to any investigational product component
• Patient with acute or chronic infections requiring treatment (active HAV, HBV, HCV, HIV, TB)
• Pregnant or lactating females
• Women of childbearing potential
• Patient who do not agrees to use effective means of contraception and not to donate sperm during the trial and up to 1 month after final administration
• Patient who participated other clinical trials of medicine or medical devices within 1 month
• Individuals who are judged inappropriate for the study by investigator