Domperidone is an antiemetic that is often prescribed for children with acute gastroenteritis in Japan. In this study, the authors assessed the efficacy of domperidone prescription in combination with oral rehydration treatment (ORT) in the treatment of vomiting during acute gastroenteritis in children during the early period. They performed a prospective multicenter randomized trial in Japan. Patients received either ORT or ORT and domperidone prescription. The primary outcome was the proportion of patients who had vomiting during the first 2 hours after randomization. A total of 56 children were eligible; 24 received ORT alone, and 32 received ORT and prescribed domperidone suppository. Results showed that 27.3% of children in the ORT group vomited as compared with 20.7% of children in the ORT and domperidone group (P = .41). In this study, it appears that domperidone in combination with ORT in the treatment of acute gastroenteritis does not reduce vomiting in the early period.