Cyclic vomiting syndrome (CVS) is a functional gastrointestinal disorder that can occur in both children and adults. Clinical courses of CVS manifesting recurrent severe vomiting episodes and interval illness may affect the long-term quality of life in children with CVS. Therefore, we should be careful in accessing a patient suggestive of CVS. Accurate diagnosis based on diagnostic criteria for CVS and the exclusion from other organic diseases mimicking clinical manifestations of cyclic vomiting is absolutely required. In patients diagnosed as CVS, optimal therapy should be performed to improve symptoms and to reduce complications in prodromal phase and emetic phase, and long-term prophylactic therapy should be tried to prevent the development of vomiting episodes. The identification of triggering factors which induce vomiting episodes might be helpful in preventing vomiting attacks. Systematic approach should be recommended to improve clinical outcome of CVS.