This is a Phase 3, randomized, double-blind, active-controlled clinical trial designed to evaluate the efficacy and safety of AG2001 in patients with acute bronchitis. The primary objective is to demonstrate the superiority of AG2001 over two active comparators based on the change in Bronchitis Severity Score (BSS) at Day 4.

Inclusion Criteria:

1. Adults aged ≥19 years to <65 years old

2. Subjects who present symptoms of Acute Bronchitis with cough and sputum symptoms within 48 hours prior the randomization visit(Visit 2) who satisfy the following

   • Total Bronchitis Severity Scale ≥ 5
   • Total Bronchitis Severity Scale sputum score ≥ 2

3. Subjects who without fever(condensed body temperature standard: less than 38.5°C) prior to randomization visit(Visit 2)

4. Subjects who present symptoms of Acute Bronchitis with cough less then 2 weeks prior to randomization visit(Visit 2)

5. Written consent voluntarily to participate who can understand the information provided in this clinical trial

Exclusion Criteria:

• Chronic respiratory diseases (e.g., COPD, asthma, pneumonia, tuberculosis, lung cancer)
• Clinically significant hepatic, renal, cardiovascular, or neurological disorders
• Use of prohibited medications (e.g., antibiotics, antivirals, corticosteroids) within the washout period
• Positive test for hepatitis B, hepatitis C, or HIV
• Pregnant or breastfeeding women
• Any condition deemed inappropriate by the investigator