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Viral gastroenteritis refers to the intestinal infection characterized by signs and symptoms like stomach cramps, watery diarrhea, vomiting or nausea, and, at times, fever.

Also referred to as stomach flu, viral gastroenteritis is commonly contracted when you come into contact with someone who is infected or consumes contaminated food or water. Healthy people have a high possibility of recovering without experiencing any complications. However, the condition can be fatal in older adults, infants, and persons with weakened immune systems.

Because there is no known effective viral gastroenteritis treatment, prevention is essential. Therefore, you should avoid potentially contaminated food or water and clean your hands frequently and thoroughly.

By Able Health I Medically reviewed by Dr. Alireza Estedlal

Page last reviewed: February 2024 I Next review due: February 2026

What is gastroenteritis?

Gastroenteritis is the inflammation of the intestine and stomach. These organs become sore and swollen due to inflammation and lead to symptoms such as vomiting, nausea, diarrhea, and abdominal pain.

Usually, gastroenteritis occurs following an infection in the gastrointestinal (GI) tract. Viruses and bacteria can cause stomach flu infections and food poisoning. Some chemicals might also lead to gastroenteritis.

Types of gastroenteritis

The most prevalent type is infectious gastroenteritis, which develops from an infection in the GI tract (stomach and intestines). Bacteria, viruses, parasites, or fungi can contribute to the infection.

Another type is chemical gastroenteritis, which can occur following ingestion of toxic chemicals that could contaminate sources of water and food. It can also result from excessive alcohol consumption or drugs such as certain medications.

Common Symptoms of Gastroenteritis

Although gastroenteritis is mostly known as stomach flu, it is different from influenza. Influenza or flu only affects the respiratory system, including the throat, lungs, and nose. However, gastroenteritis attacks the intestines and causes the following signs and symptoms:

  • Watery, often non-bloody diarrhea. Having bloody diarrhea normally indicates a different and more serious infection.
  • Vomiting, nausea, or both
  • Stomach pain and cramps
  • Infrequent headaches or muscle aches
  • Low-grade fever

Based on the underlying cause, the symptoms of viral gastroenteritis can emerge within 1 to 3 days after infection, ranging from mild to severe. Typically, the symptoms last for only one or two days, but in rare cases, they might last for 14 days.

The similarity of the symptoms can make it difficult to distinguish between viral diarrhea and diarrhea triggered by bacteria like Clostridioides difficile, Escherichia coli, and salmonella or parasites, including giardia.

Causes of Gastroenteritis

The chances of getting viral gastroenteritis are higher when you drink or consume water and foods that are contaminated. Also, sharing towels, food, or utensils with an infected person increases the risk of the condition.

Some of the viruses that can trigger gastroenteritis are:

  • Noroviruses: This infection affects both minors and adults and is the leading cause of foodborne illness in the world. Norovirus can spread rapidly in families and communities, particularly among those in confined areas.

    Mostly, the virus is contracted through contaminated water or food, but it could also be transmitted among individuals sharing food or who are in close contact. In addition, one can be infected by touching contaminated surfaces and then putting hands in the mouth.
  • Rotavirus: This is the leading cause of viral gastroenteritis among children in the world. They often get the virus by putting fingers or contaminated objects into their mouths, and it could also be transmitted by eating contaminated foods. This infection tends to be highly severe in young kids and infants.

Adults who have rotavirus might not exhibit any symptoms. However, they can still pass on the virus, and this is especially concerning in institutional settings like nursing homes, as infected adults can unknowingly spread the infection to others.

Viral gastroenteritis vaccination is available in certain nations, including the US and is effective in the prevention of the infection.

Furthermore, consuming some shellfish, particularly undercooked or row oysters, could cause the illness. On the other hand, drinking contaminated water contributes to viral infection. However, in most cases, the infection is transmitted when an infected person touches food without cleaning hands after visiting the toilet.

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Risk factors

Gastroenteritis is a global illness affecting everyone regardless of their age. Persons who are likely to be more vulnerable to the condition are:

  • Younger children: Minors in elementary schools or care centres are at a higher risk of gastroenteritis since their immune systems are not yet matured.
  • Older adults: The immune systems of adults usually become less efficient with age. Hence, older people, especially those in nursing homes, are more susceptible. This is due to weakened immune systems and being in close contact with persons who may spread the germs.
  • Schoolchildren and dormitory residents: Places where groups of individuals meet, especially in confined areas, can facilitate the spread of intestinal infection.
  • Having a weak immune system: People with compromised immune systems, such as those with HIV/AIDS, undergoing chemotherapy, or having another health problem, are at a higher risk. This is because they have low resistance to infection.

Every gastrointestinal virus has an active season. For example, people residing in the northern hemisphere have an increased risk of getting norovirus or rotavirus infection during spring and winter.


The major viral gastroenteritis complication is dehydration, which is a serious loss of water and vital minerals and salts in the body. Dehydration, however, should not be a concern in healthy people who replace lost fluids from diarrhea and vomiting by drinking enough water.

Older adults, infants, and individuals with a weak immune system may suffer severe dehydration from losing more fluids. They might thus require to be hospitalized for fluid replacement through an IV. In rare cases, dehydration can cause death.

Who is at risk of developing gastroenteritis?

Anybody can get gastroenteritis, but some groups of people tend to be more vulnerable. They include:

  • Children: Kids, particularly those in daycare and school settings, have an increased risk of gastroenteritis because of their immature immune systems and proximity to others.
  • Elderly: Age-related immune system alterations and certain medical conditions increase the risk of developing gastroenteritis among older people.
  • Compromised immune systems: Those with weakened immune systems, due to chemotherapy and HIV/AIDS are more vulnerable to infections like gastroenteritis.
  • Travellers: People traveling to places with poor hygiene and sanitation practices might be at a high risk of getting gastroenteritis infection.

When to Seek Medical Attention for Gastroenteritis


Contact your doctor if you experience any of these:

  • Not being able to keep fluids down for 24 hours
  • Vomiting or diarrhea that lasts for more than 2 days
  • Vomiting blood
  • Dehydration signs such as dry mouth, excess thirst, little or no urine, deep yellow urine, light-headedness or dizziness, and severe weakness.
  • Blood in bowel movements
  • Intense stomach pain
  • Fever that is more than 104 F (40 C)

Infants and children

Seek immediate medical attention if your child has these symptoms:

  • High fever of 102 F (38.9 C) or above
  • Exhausted and very irritated
  • A lot of pain or discomfort
  • Bloody diarrhea
  • Dehydrated: Look out for dehydration signs in ill children and infants, including unusual or reduced drinking and urination amount, thirst, crying with no tears, and dry mouth.

Keep in mind that although spitting might be common in infants, vomiting isn’t. Normally, babies can vomit for various reasons, most of which need medical care.

Therefore, you should immediately contact your child’s doctor if you notice the following:

  • Frequent vomiting
  • Not wetting a diaper in 6 hours
  • Severe diarrhea or bloody stools
  • Sunken fontanel (soft spot) on the top of the head
  • Dry mouth or crying without tears
  • Unusual drowsiness, sleepy or unresponsive

Diagnosis of Gastroenteritis

Viral gastroenteritis can be diagnosed based on the symptoms, physical examination, and if there are similar infection cases within the community. Norovirus and rotavirus can be detected through a rapid stool test, though quick tests for viruses causing gastroenteritis aren’t available. Sometimes, the practitioner can order stool samples to help rule out a potential parasitic or bacterial infection.

Treatment Options for Gastroenteritis

In many cases, gastroenteritis treatment is supportive, which focuses on supporting the natural recovery process of the body instead of curing the illness. The treatment options can include:

  • IV fluids: This helps prevent or address imbalances of electrolytes and dehydration.
  • Parenteral nutrition: Provides energy in the body without the use of a stressed digestive system.
  • Medications: Helps treat symptoms such as diarrhea and nausea in some cases.

Certain acute gastroenteritis causes, however, may require medications to resolve. For instance, a specific antiparasitic or antibiotic drug may be needed to treat a particular form of parasite or bacterial infection.

For chemical gastroenteritis caused by toxic poisoning, more treatment may be required to clear out the toxin from the body. The toxin and the condition will determine the type of treatment.

Home Remedies for Gastroenteritis

Apart from medical treatment, various home remedies are available that can ease symptoms and promote recovery from the illness. Clear liquids like water, broth, or herbal teas can assist in preventing dehydration and providing vomiting and nausea relief.

Doctors usually recommend the BRAT (banana, rice, applesauce, toast) diet since it’s gentle on the stomach and contains easily digestible carbohydrates. In addition, probiotics (vital bacteria) can aid in the restoration of gut flora balance and promote healing. On the other hand, ginger, which can be taken as tea or while raw, helps soothe the digestive system and ease nausea.

Medications for Gastroenteritis

Some drugs can help manage particular symptoms associated with stomach flu. Antiemetics, which includes metoclopramide or ondansetron, can help alleviate vomiting and nausea. Similarly, antidiarrheal drugs like loperamide or bismuth subsalicylate can manage diarrhea. It is, however, essential to know that these medicines need to be taken cautiously and under medical supervision. This is because they can disrupt the natural defence system of the body and potentially prolong infection.

Prevention of Gastroenteritis

Consider the following precautions to avoid spreading intestinal infections:

  • Vaccinating your child: Vaccination against rotavirus-causing stomach flu is available in certain nations, like the United States. Administered during the first year of life in children, the vaccine effectively prevents severe gastroenteritis symptoms.
  • Washing hands thoroughly: Always ensure that both you and your child wash your hands. If your kid is old enough, educate them on how to wash their hands, particularly after visiting the toilet.

    Also, you should wash your hands before you cook or eat food and after changing diapers. Using warm water and soap and scrubbing for at least 20 seconds is advisable. Ensure that you clean under the fingernails, around the cuticles, and hand creases, then thoroughly rinse. Consider carrying hand sanitizer and sanitizing wipes to use as alternatives when water and soap are not accessible.
  • Using separate personal items at home: Do not share eating utensils like plates, cups and glasses. Also, consider using separate towels in the bathroom.
  • Preparing your food safely: Always rinse fruits and vegetables before you eat them and clean the kitchen tops before using them to prepare food. Also, avoid cooking food if you are ill.
  • Keeping distance: If possible, avoid coming into close contact with an infected person.
  • Disinfecting hard surfaces: Disinfect hard surfaces like counters, doorknobs, and faucets if you are living with someone who has viral gastroenteritis. Use a solution of 73 to 369 millilitres (5 or 25 tablespoons) of household bleach and 3.8 litres or a gallon of water.
  • Handling laundry carefully: Put on gloves when handling laundry if someone has viral gastroenteritis in your home. Rinse bedding and clothes in hot water and ensure that you dry them under hot sunlight. Thoroughly clean your hands afterwards.
  • Checking out your kid’s care centre: Ensure that the care centre where you take your child has different rooms for cooking/serving food and changing diapers. Also, the diaper-changing area should have a sink and a sanitary method for disposing of used diapers.

Take precautions when traveling

To lower the risk of getting ill from contaminated food and water while traveling to other countries, consider these useful tips:

  • Only taking well-sealed bottled or carbonated water.
  • Avoiding ice cubes as they might be made using contaminated water.
  • Using bottled water when brushing your teeth.
  • Avoiding raw foods, including raw vegetables, peeled fruits or salads, which human hands have handled.
  • Avoiding undercooked fish and meat.