Objectives The purpose of this study is to evaluate the clinical effectiveness and prophylactic treatment effectiveness of Gagam-Bopyeyangyeongjeon(GGBYJ) on the Lung Weakness Children(肺系虛弱兒) who catch cold easily. Methods The study has been carried out from 27 children, who were treated with GGBYJ in Department of Pediatrics, $igcircigcirc$ Oriental Medical Hospital from August to December in 2009. The study was completed through patient chart review and telephone survey. Results 1. Immediately after the treatment, there was significantly decreasing(p=0.005) on respiratory symptoms in the Lung Weakness Children(肺系虛弱兒) who catch cold easily. 2. After the treatment, when season changes (three months later), there were preventive and continuous effects on reducing morbidity and on decreasing degree of symptoms against new respiratory infections compared to the previous year before taking medicine. 3. GGBYJ improved the respiratory symptoms, and also anorexia, constipation, heights, skin and fatigue. Conclusions In conclusion, there were significant clinical and preventive effectiveness of GGBYJ for the Lung Weakness Children(肺系虛弱兒) who caught a cold easily. Further studies are needed with more clinical cases.