Objectives: The purpose of this study is to investigate the frequency of side effects, and the range of the side effects from Korean herb medicine on children. Methods: The study has been carried out from 212 children who took Korean herb medicine in Department of Pediatrics, $igcirc;igcirc$ Oriental Medical Hospital from September 2009 to February 2010. The study was completed through patients chart review and telephone survey. Results: 1. There were 6 side effect cases on male, and 3 side effect cases on female out of 212 children. The incidence of side effect was 4.2%. 2. The most common side effect was abdominal pain. The most common related organ was digestive organ. 3. The side effect occurred within one to three days after taking Korean herb medicine, and the symptoms were mostly disappeared after taking the Korean herb medicine into divided dose or less dose. Conclusions: The symptom of side effects on children was not as severe as other adverse drug reactions often seen in Western medication. The most common symptom was abdominal pain. Further studies are needed.