Ondansetron vs Prochlorperazine for Nausea and Vomiting in the Emergency Department

Inclusion Criteria: * Patients presenting to the ED with at least one of the following * Nausea * Vomiting documented in the ED Exclusion Criteria: * Previous treatment in the ED with Ondansetron, prochlorperazine, promethazine or metaclopramide * Patients with missed last menstrual period * Pregnancy * Age \< 18 years old * Treatment with antineoplastic agents within 7 days prior to randomization * Irritable bowel syndrome * Gastroparesis * Suspected gastrointestinal bleed * Suspected intestinal obstruction * Preexisting motor disorder (Restless-leg syndrome or Parkinson's disease) * Traumatic brain injury upon admission to ED * Intracranial hemorrhage upon admission to ED * Patients unable to read, write or communicate in the English language * Patients leaving the ED against medical advice