Dimenhydrinate, an over-the-counter, widely used drug in Canada, is an ethanolamine-derivative anti-histamine. It limits the stimulation of the vomiting center by the vestibular system, which is rich in histamine receptors. Multiple studies have shown its effectiveness in treatment of post-operative nausea and vomiting in children. It is also used for treatment of vertigo in children. Furthermore, it has the potential to be much more cost-effective than ondansetron, with an average cost of $0.90 US per dose . Its principal side effects are drowsiness, dizziness and anticholinergic symptoms. Restlessness and insomnia have also been described in children. To date, there has been no published data on the efficacy of dimenhydrinate in controlling emesis in children with acute gastroenteritis.