A Multicenter, Randomized, Double-blind, Parallel Group Study to Determine the Optimal Dose of HL301 After 7 Days Oral Administration in Acute Bronchitis or Acute Exacerbations of Chronic Bronchitis Patients (HL301: Mixed Extract of Rehmannia Glutinosa, Schisandra and so on)

Inclusion Criteria: 1. Both gender, 19 years ≤ age ≤ 80 years 2. Acute bronchitis or acute exacerbations of chronic bronchitis patients with BSS(Bronchitis Severity Score)\* ≥ 5point at Visit1 and Visit2 3. Written consent voluntarily to participate in this clinical trial Exclusion Criteria: 1. Patients who were increased the bleeding tendency 2. Patients with any of Alanine aminotransferase, Aspartate aminotransferase or serum Blood Urea Nitrogen, Creatinine\> 2 times of the normal upper range 3. Patients who investigators determines to severe respiratory disease that would interfere with study assessment 4. Patients with COPD(Chronic Obstructive Pulmonary Disease) history of stage 3 or more 5. Patients who were treated with oral systemic adrenocortical hormone or immunosuppressive drug within 4 weeks prior to study participation 6. Patients who were treated with oral β2-agonist, anticholinergic, Methylxanthine, antibiotics, antihistamines, sympathomimetic agent or oriental medicine/health functional food for antitussive and mucolytic Effect within 1 weeks prior to study participation 7. Patients who were treated with oral Antitussive, Mucolytic Agents,systemic antimicrobial agent within 3 days prior to study medication dosing 8. Patients with drug or alcohol abuse 9. Patients with clinically significant active liver, renal, cardiovascular, respiratory, endocrine, central nervous system disease or history of malignant tumor or mental illness(except no relapse for 5 years after surgery) 10. The aged person with severe medical history which is mental disorder(dementia), cancer, chronic renal failure, chronic liver failure 11. Pregnant or breast-feeding 12. Patients currently participating in or has participated in other clinical study within 30 days prior to study participation 13. Patients who investigators determines not appropriate to take part in this clinical study