Background:Cyclic vomiting is an uncommon disorder that can be described as recurrent, self-limiting, fairly uniform episodes of intractable nausea and vomiting with no identifiable organic cause, separated by symptom-free intervals. There is no established therapeutic regimen for this disorder.Methods:Fourteen children referred to the Pediatric Gastroenterology Clinic were diagnosed with cyclic vomiting from May 1984 to January 1995. Vomiting, the predominant symptom, was present in all children and was severe enough to require hospitalization in 11. Associated symptoms included abdominal ain, headache, nausea, aura, and fever. Diagnostic studies were done to rule out organic causes as indicated in individual patients. Daily phenobarbital was prescribed in all 14 patients. The dose ranged from 30 to 120 mg/hr (mean 2 mg · kg-1· day-1), with a median dose of 60 mg/hr. Prior therapy with propranolol (3 patients) and butalbital (2 patients) had been ineffective.Results:Eleven patients had complete resolution of their symptoms, and 3 patients had marked improvement in their symptoms with infrequent attacks of reduced severity. The only side effects associated with long-term phenobarbital therapy were behavioral in nature, namely hyperactivity and disruptive behavior at school.Conclusions:The results of our series of 14 patients, all of whom received barbiturates, support the usefulness of this therapeutic approach. Hence we feel that daily low-dose phenobarbital therapy is a safe and effective therapy in preventing episodes of cyclic vomiting in children.