Nausea and vomiting occur when the emetic center, located in the medulla, has been stimulated. The emetic center is also known as the true vomiting center (TVC). The TVC is both a motor and a reflex center that regulates and coordinates the sequence of events associated with vomiting. It may be stimulated by afferent fibers from distal locations (primarily those from the gastrointestinal tract, vestibular apparatus, cerebral cortex, and heart) or by the chemoreceptor trigger zone (CTZ) also located in the medulla(1). Chemicals, drugs, or toxic substances in the blood activate the CTZ. Efferent pathways include the phrenic, spinal, and visceral efferent nerves.