Vomiting (emesis) in animals is the active, forceful ejection of stomach and upper intestinal contents through the mouth, often preceded by signs of nausea such as drooling, excessive swallowing, and restlessness. It is a complex reflex act initiated by the vomiting center in the brain stem and involves significant abdominal muscle contractions. While it serves as a protective mechanism against toxins, it is a non-specific symptom of many underlying health issues, ranging from mild dietary indiscretion to serious illnesses.