Objective:To study the clinical effect of herba Houttuyniae Injection by aerosol inhalation for respiratory tract infection. Methods: 107 patients with respiratory tract infection (the main symptoms were cough and expectoration) were treated with Herba Houttuyniae Injection by aerosol inhalation. The conditions of symptom improvement and bacteria in sputum before and after treatment were observed. The case control studies on parts of patients in acute attack and delayed peroids of chronic bronchitis were carried out. The treatment processes patients were given 25mL Herba Houttuyniae Injection and 25mL normal saline by aerosol inhalation for 30 minutes, twice a day. Results: The effective rates were 91.59% for cough symptom, 85.06% for expectoration symptom. 98.13% patients experienced comfort of pharyngeal and thoracic protions after treatment. Among 55 patients whose cough symptom wasn't improved after they were treated with anti inflammatory agent and antitussive the effective rate was 72.72% after treatment with Herba Houttuyniae Injection by aerosol inhalation. The 45 case control studies of acute attack and delayed periods of chronic brochitis showed no statistically difference between them. The clearance rate of bacteria in sputum after treatment was 80.39%. Conclusions: Herba Houttuyniae Injection by aerosol inhalation is effective for respiratory tract infection with the main symptoms of cough and expectoration.