Viral Gastroenteritis (Stomach Flu): Symptoms, Causes, and Treatment

Viral gastroenteritis is a disease that affects millions of people each year, especially young children. Fortunately, early diagnosis and treatment lower the risk of complications.
Viral Gastroenteritis (Stomach Flu): Symptoms, Causes, and Treatment

Last update: 16 December, 2022

Gastrointestinal diseases are one of the main reasons for medical consultation around the world. Gastroenteritis, diarrhea, irritable bowel, and gastroesophageal reflux are some of the most common conditions. Are you interested in learning more about viral gastroenteritis? We’ll tell you all about it in this article!

Viral gastroenteritis is also called stomach flu. It’s an infectious disease of viral origin that causes inflammation of the inner lining of the stomach and small intestine. The condition usually causes diarrhea and abdominal pain accompanied by nausea or vomiting.

Babies and young children are susceptible to this type of infection and can get it more than once a year. In fact, studies estimate that more than 10% of hospitalizations of children under 5 years of age in developed countries are due to this condition.

Symptoms of viral gastroenteritis

Viral gastroenteritis causes diarrhea.
In addition to the typical abdominal pain, viral gastroenteritis is usually accompanied by watery diarrhea for a few days.

In most cases, people associate the term stomach flu with influenza or the common flu. However, influenza only affects the nose, throat, and lungs, while gastroenteritis affects the digestive tract.

The clinical symptoms usually appear between 4 and 72 hours after contact with the virus. Some of the common symptoms and signs of viral gastroenteritis include the following:

  • Watery diarrhea
  • Nausea and vomiting
  • Abdominal discomfort and cramps
  • Fever and chills

Similarly, young children often show signs of dehydration early. The symptoms are usually more severe and include the following:

  • Excessive thirst and a dry mouth
  • Urinating little or not at all
  • Intense yellow or dark urine
  • Weakness and lightheadedness

Symptoms generally last one to two days, However, they can also persist for up to 10 days. In adults, the condition is often confused with other conditions, such as irritable bowel syndrome and inflammatory bowel disease.

When to seek medical attention?

Severe viral gastroenteritis can be life-threatening if it isn’t treated in time. Some of the warning signs that suggest the need for medical attention as soon as possible include the following:

  • A fever of 39 degrees Celsius (102 Fahrenheit) or more in children and 40 degrees Celsius (102 Fahrenheit) in adults
  • Constant diarrhea and vomiting for more than 2 days
  • Bloody stools
  • Signs of dehydration


The viruses responsible for this disease are usually transmitted through ingesting contaminated food or water, as well as having close contact with infected people. Additionally, utensils, dishes, and towels can act as vehicles for the germ.

Norovirus, rotavirus, astrovirus, adenovirus, calicivirus, and hepatitis A virus are the main causative agents of gastroenteritis. COVID-19 infection can also cause stomach flu symptoms, even in the absence of respiratory disease.

Some research affirms that rotavirus is the most common cause of viral gastroenteritis in children, accounting for more than 500,000 deaths a year. Rotavirus infection in infants and young children is preventable by vaccination during the first months of life.


The diagnosis of viral gastroenteritis focuses on identifying the classic symptoms of the disease. In this sense, the doctor must carry out a detailed questioning of the patient, diet, habits, lifestyle, and recent trips. A physical examination can identify signs of abdominal discomfort.

The health professional may also ask for a stool exam. This gives results about the macroscopic and microscopic characteristics of the fecal material, and allows us to differentiate if gastroenteritis is of viral, bacterial, or parasitic origin.

Currently, there are rapid tests for the detection of rotavirus and norovirus in stools. However, the rest of the causal agents lack this type of analysis.


Viral gastroenteritis is treated in several ways.
To control symptoms, it’s important to rest, take care of eating and, when necessary, to take specific drugs.

Viral gastroenteritis is usually self-limiting, so most people can get better without medical treatment. For this reason, the treatment plan is usually aimed at alleviating symptoms and avoiding short-term complications. Some of the indications are the following:

  • Bed rest
  • Drinking plenty of water
  • Drinking sports drinks (only in adults)
  • Using oral rehydration solutions such as Pedialyte, Naturalyte, Infalyte and CeraLyte
  • Using antidiarrheals, such as loperamide, but only in adults under medical supervision.
  • Not taking antibiotics
  • Maintain breastfeeding in children.

Doctors may recommend the use of probiotics as part of the treatment of diarrhea. These are live microorganisms that restore the gastrointestinal microbiota. However, there’s no formal recommendation for viral gastroenteritis, so they should be consumed under strict medical indications.

Prevention is key in viral gastroenteritis

Viral gastroenteritis is an infectious disease that’s often associated with poor hygiene conditions. In this sense, the correct handling of food, the consumption of uncontaminated water, and the proper washing of hands are key in the prevention of this infection.

On the other hand, in young children, vaccination is essential in order to prevent different viral infections. If you have any strange stomach symptoms that are accompanied by diarrhea and vomiting, don’t hesitate to seek medical attention. Health professionals are the only ones trained to guide you in the resolution of conditions and illnesses like this.

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