Digestive diseases

Viral gastroenteritis

Digestive diseases
Viral gastroenteritis
Last update: 17-10-2023

How else can it be called?

  • Stomach flu

  • Norwalk virus infection

  • ICD-10: A08.3

What is viral gastroenteritis?

Viral gastroenteritis is an infection caused by various viruses (rotavirus, adenovirus and especially the Norwalk virus), which produces inflammation of the lining of stomach and intestines.

The virus infiltrates the stomach and intestines causing inflammation of their linings. Consequently, these organs are temporarily impaired and food rejection occurs in the form of vomiting and diarrhea.

The acute condition usually last for one to three days.

The body fluids of infected people contain the virus, sometimes even before symptoms appear.

The virus can be transmitted through direct contact with an infected person or by sharing food, drinks, or eating utensils.

What are the main symptoms of viral gastroenteritis?

The most common symptoms are:

  • Nausea and vomiting.
  • Stomach cramps with pain in the abdomen.
  • Watery diarrhea, rarely with blood.
  • Moderate fever.
  • Fatigue and muscle pain.
  • Chills.
  • Loss of appetite.

Symptoms may appear gradually, starting with fatigue and muscle aches and then progressing to vomiting and diarrhea. Alternatively, there could be a sudden onset of nausea and vomiting with diarrhea. In children it usually begins with vomiting and in adults with diarrhea.

The most significant complication, especially in children, is dehydration which can even lead to death.

How can it be detected?

The diagnosis is based on clinical observations. The presence of symptoms of viral infection includes moderate fever, fatigue and muscle pain, as well as chills and, notably, the onset of gastrointestinal symptoms like vomiting and diarrhea.

The presence of similar symptoms in other relatives or in the immediate environment strongly supports the diagnosis.

A stool sample may be needed if a complicated infection is suspected, such as when symptoms worsen or if there is diarrhea with mucus, blood, or pus. In case of doubt, appendicitis should be ruled out.

Which is the recommended treatment?

To prevent dehydration, it is important to continue providing food in adults and breast milk in babies. For older children and adults, it is recommended to offer easily digestible options such as rice water, carrot soup, lentil or potato soups, defatted broths, fresh fruit juices, green coconut water, and infusions. Even water, can be helpful to maintain fluid intake.

The most effective way to rehydrate is through oral rehydration salts (ORS), whether they are commercially available or homemade. Beverages high in sugar, like sports drinks or carbonates drinks, are not recommended as they can exacerbate dehydration.

The patient is given half to a cup, or as much as they can tolerate after each episode of diarrhea, administered in small sips or teaspoons to prevent vomiting. If vomiting occurs, the intake is slowed down until it stops vomiting. Flavoring oral rehydration solutions are available in the market (in sachets) to be diluted in a litre of water.

In the diet, you should avoid fatty foods such as fast foods and fried foods, as well as acidic foods (such as orange juice) or those containing caffeine (like coffee). Additionally, it is essential to completely remove dairy products (milk, cheese, yogurt) from the diet for a few days.

Gradually, you can reintroduce easily digestible soft foods into your diet, such as white fish, rice, cooked carrots, meat soups, and omelets. You can start eating these foods after around three days, once all symptoms of the illness have disappeared.

Antibiotics and antidiarrheal are not recommended, since the condition must evolve naturally and these medications can cause complications, particularly by concealing signs of a more severe illness. The doctor is the only one who can decide when to use this type of medication.

Dehydration is a significant complication of viral gastroenteritis and if there is persistent vomiting and diarrhea it is important to look for medical attention.

Viral gastroenteritis typically resolves within one to three days. However, it may take one to two weeks before bowel habits completely return to normal.

Finally, prevention plays an important role. In places without safe water, water must be treated or only bottled water should be consumed. People with viral gastroenteritis should prevent spreading the infection by washing their hands, cleaning contaminated items and surfaces and avoiding getting involved in food preparation.

Medically reviewed by Yolanda Patricia Gómez González Ph.D. on 17-10-2023


  • Pathology of the Gastrointestinal Tract, 2017, Fátima Carneiro, Paula Chaves, Arzu Ensari, ISBN 978-3-319-40559-9, Pag. 688.
  • Diagnostic Pathology of Infectious Disease. 2nd edition. Richard L. Kradin. 2018. ISBN: 978-0-323-44585-6. Pág. 81.
  • Harrison’s, Principles of Internal medicine, 20th Edition (2018). Chapter 198: Viral Gastroenteritis. Pág. 5987. McGRAW-HILL EDUCATION. ISBN: 978-1259644030.
  • Viral gastroenteritis (stomach flu). Available on: https://www.mayoclinic.org

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