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

• Both gender, 19 years ≤ age ≤ 80 years
• Acute bronchitis or acute exacerbations of chronic bronchitis patients with BSS(Bronchitis Severity Score)* ≥ 5point at Visit1 and Visit2
• Written consent voluntarily to participate in this clinical trial

Exclusion criteria

• Patients who were increased the bleeding tendency
• Patients with any of Alanine aminotransferase, Aspartate aminotransferase or serum Blood Urea Nitrogen, Creatinine> 2 times of the normal upper range
• Patients who investigators determines to severe respiratory disease that would interfere with study assessment
• Patients with COPD(Chronic Obstructive Pulmonary Disease) history of stage 3 or more
• Patients who were treated with oral systemic adrenocortical hormone or immunosuppressive drug within 4 weeks prior to study participation
• 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
• Patients who were treated with oral Antitussive, Mucolytic Agents,systemic antimicrobial agent within 3 days prior to study medication dosing
• Patients with drug or alcohol abuse
• 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)
• The aged person with severe medical history which is mental disorder(dementia), cancer, chronic renal failure, chronic liver failure
• Pregnant or breast-feeding
• Patients currently participating in or has participated in other clinical study within 30 days prior to study participation
• Patients who investigators determines not appropriate to take part in this clinical study