emesis

Emesis, commonly known as vomiting, is the forceful expulsion of stomach contents through the mouth. It is a reflex driven by the vomiting center in the medulla, coordinated with the chemoreceptor trigger zone and autonomic pathways. Nausea frequently precedes emesis, but vomiting can occur without warning.

Causes are diverse and include gastrointestinal infections, food poisoning, and other GI disorders; pregnancy, especially early pregnancy; medications such as chemotherapeutics, opioids, and antibiotics; motion sickness and vertigo; toxins such as alcohol; and central nervous system disorders or metabolic disturbances.

Assessment focuses on dehydration and electrolyte balance, and on red flags such as hematemesis, severe abdominal pain, confusion, fever, or vomiting lasting beyond 24–48 hours. The appearance of the vomit (clear/bloody/bilious) may aid diagnosis. Initial evaluation may include history, examination, and basic labs as indicated.

Management aims to treat the underlying cause and prevent complications. Hydration and electrolyte correction are central; antiemetics such as 5-HT3 antagonists (ondansetron), dopamine antagonists (metoclopramide or prochlorperazine), or antihistamines may be used. Special situations include pregnancy, where safer antiemetics are preferred, and chemotherapy, where additional agents (e.g., neurokinin-1 antagonists) can improve control. Severe or persistent vomiting may require hospital care and further investigation.