A Phase II Clinical Study of PDC-748 in Patients With Acute Cough

Inclusion Criteria: * Patients diagnosed with acute cough ; * Men or women aged ≥ 20 years old; * Patients with Cough Symptom Score(daytime) between 2 and 4, inclusively; * Patients are willing and able to comply with the study procedures and sign the informed consent. Exclusion Criteria: * Patients with chronic cough ; * Patients with chronic airway disease; * Patients with respiratory tract malignancy; * Patients with clinically suspected low respiratory tract infection; * Patients with abnormal liver or kidney functions * Patients taking antitussives, sleeping pills, sedative medications, or herbal products; * Pregnant or breastfeeding patients; female patients of child bearing potential who do not agree to practice effective birth control; * Patient's symptom of acute cough may be due to heart failure or may be induced by other medications such as ACE inhibitor medications, as determined by the investigator; * Patients who have a history or evidence of a medical condition that would expose them to an undue risk of a significant adverse event or interfere with the assessments of safety or efficacy during the course of the trial, including but not limited to hepatic, renal, respiratory, cardiovascular, endocrine, immune, neurological, or hematological disease as determined by the clinical judgment of the investigator; * Use of any investigational drug or participation of any clinical trial within 28 days prior to this study.