Cyclic vomiting syndrome (CVS) is a debilitating functional gastrointestinal disorder. Diagnosis is based on the Rome III criteria. There are no evidence-based guidelines for the management of paediatric CVS, although ondansetron and antimigraine medications are frequently tried. We describe a 13-year-old adolescent girl with severe CVS and numerous hospital admissions for dehydration because of cyclic vomiting. She had failed oral ondansetron therapy. Oral aprepitant (125 mg in the first, and 85 mg on the second and third days), a neurokinin 1 receptor antagonist that has been approved for preventing chemotherapy-induced vomiting or postoperative emesis, was tried in our patient at home during the first prodromal signs of an upset stomach. She had a dramatic response to it, with no further episodes of vomiting since its start. There is an urgent need for randomised clinical studies to assess the efficacy of available treatment options, including aprepitant in patients with severe CVS.