Abstract: Objective To evaluate the clinical efficacy and safety of neurokinin 1 receptor antagonists (NK- 1 RA) for the prevention of nausea and vomiting induced by highly emetogenic chemotherapy (HEC) in children with cancer. Methods The pediatric patients who received NK-1RA to manage nausea and vomiting caused by HEC between May 2020 and December 2020 were enrolled in this study. The children treated with fosaprepitant in combination with ondansetron and dexamethasone were enrolled in the fosaprepitant group, and the children treated with aprepitant in combination with ondansetron and dexamethasone were included in the aprepitant group. The clinical efficacy and safety of the two groups were compared after treatment. Results A total of 122 children ( 83 boys and 39 girls) were included. The median age was 8 . 0 ( 4 . 8 ~ 11 . 0 ) years. Sixty-two patients were included in the fosaprepitant group and 60 in the aprepitant group. After NK- 1 RA was used to prevent chemotherapy-induced nausea and vomiting (CINV), the complete remission (CR) rate of acute, delayed, and overall vomiting (i.e., non-vomiting rate) was 88 . 5 %, 71 . 3 % and 65 . 6 %, respectively. In the stage of acute vomiting, there was significant difference in the distribution of vomiting severity between the fosaprepitant group and aprepitant group (P

Key words: NK- 1 receptor antagonist; aprepitant; fosaprepitant; child