How common is vomiting in gastroenteritis?

Gastroenteritis inflames the stomach or intestines, commonly causing a short-lived combination of vomiting and diarrhoea. It may spread between people through contaminated hands, surfaces, food, or drink. Vomiting does not by itself identify gastroenteritis, because several digestive and non-digestive illnesses can cause it. The amount of fluid lost matters more than the number of episodes, particularly for children, older adults, and people with other health problems.

After vomiting, wait briefly before trying tiny sips of water or an oral rehydration drink. Increase the amount gradually if it stays down. Eat simple foods when appetite returns, and avoid alcohol until you are recovered. Wash hands thoroughly, clean shared bathroom surfaces, and avoid preparing food for other people while symptoms continue. Rest, and keep track of urine and your ability to drink.

Seek urgent care for blood in vomit or stool, severe abdominal pain, confusion, fainting, breathing difficulty, or marked dehydration such as very little urine. Get prompt advice if vomiting prevents drinking, diarrhoea is severe, fever is high, or symptoms affect a vulnerable person. Medical review is also appropriate when symptoms persist, worsen, or improve and then return.

How should I replace fluids and salts? Could my medicines be worsening the vomiting? When is it safe to return to work or school? What signs mean I need same-day assessment?