Gastroenteritis
(Stomach Flu)

Gastroenteritis Summary
Gastroenteritis (viral gastroenteritis, stomach flu) is an infection caused by a variety of viruses that results in vomiting and/or diarrhea. Even though it is often called the "stomach flu," it is not caused by the influenza viruses. Viruses that can cause gastroenteritis (stomach flu) include: rotaviruses, adenoviruses, caliciviruses, astroviruses, Norwalk virus, and a group of Noroviruses. Gastroenteritis is not caused by bacteria. The main symptoms of gastroenteritis include vomiting and watery diarrhea, however, headache, fever, and abdominal cramps (stomach ache) may also be present.
Medical Author:
Medical Editor:

Gastroenteritis (stomach flu) facts

  • Gastroenteritis is inflammation of the stomach, intestines, or both.
  • There are many causes of gastroenteritis; the most numerous cases are caused by viruses, followed by bacteria and other agents.
  • The major gastroenteritis symptoms of diarrhea, nausea, vomiting, and abdominal cramps; symptoms usually self-resolve in 2 to 5 days.
  • The majority of gastroenteritis disease is very contagious, especially those caused by viruses and bacteria; a few causes of gastroenteritis are not contagious.
  • Gastroenteritis usually is not a serious illness unless the affected person becomes dehydrated or an elderly person becomes infected with Norovirus and especially, Clostridium difficile.
  • Most food, fluids, and other items become contaminated with causative agents of gastroenteritis from direct or indirect contact with a person that has the disease.
  • Most individuals have some risk of encountering gastroenteritis; people that live in close contact with others (for example, live on a ship, in a dorm, or barracks) have a higher risk.
  • People who become dehydrated should seek medical care; if the symptoms become worse or are accompanied with other symptoms and/or last longer than about 5 days, the person should seek medical care as they may have a more serious disease.
  • Gastroenteritis is frequently presumptively diagnosed by the symptoms; infrequently, culture and identification, usually with immunological tests, of the causative agent is done during large outbreaks of the disease.
  • Most people self-limit gastroenteritis in 2-5 days and require no treatment as long as they remain well hydrated. IV hydration may be needed by some people. Some clinicians treat the symptoms of nausea, vomiting, and diarrhea with medications, others do not.
  • The major complication of gastroenteritis is dehydration; in addition, pseudomembranous colitis may occur with Clostridium difficile infection.
  • Hand washing, good hygiene, washing produce, cooking foods adequately, and drinking only treated or pasteurized fluids can help prevent gastroenteritis.
  • The prognosis for gastroenteritis is usually excellent, unless dehydration occurs or an elderly person's treatment is not started early in the infection.

Patient Comments

Viewers share their comments

Gastroenteritis (Stomach Flu) - Effective Treatments Question: How long did the symptoms of your stomach flu last? Was there anything in particular that helped with pain/symptom relief?
Gastroenteritis (Stomach Flu) - Diagnosis Question: How was your gastroenteritis (stomach flu) diagnosed?
Gastroenteritis (Stomach Flu) - Symptoms Question: What were the symptoms associated with your stomach flu?
Gastroenteritis (Stomach Flu) - Causes Question: If known, what do you think caused stomach flu in you, a friend, or relative?