Vomiting is seen as a symptom in patients with brain tumors, but it rarely leads to the diagnosis in the absence of a recognized neurologic deficit. Five patients were referred to a pediatric gastroenterologist for outpatient evaluation of persistent vomiting and were subsequently found to have an intracranial mass lesion. The paucity of neurologic findings and the absence of headaches in most of these patients caused the referring physicians to focus on the gastrointestinal tract and not the central nervous system as the cause of the patients' vomiting. The pathophysiology of vomiting and evaluation of these patients is discussed; recognizable patterns of vomiting in these patients are described.