Stomach bugs can be highly contagious and cause unpleasant symptoms such as vomiting and diarrhea. Many viruses, such as norovirus and rotavirus, can cause stomach bugs.

Stomach bugs, or stomach flu, are other terms for viral gastroenteritis. This term refers to when viruses irritate and inflame the stomach or intestines, which causes the characteristic symptoms of stomach bugs.

Many different viruses can cause gastroenteritis. These viruses can often live on surfaces and in foods and drinks, which are common places for a person to come into contact with them.

Read on to learn more about the different types of stomach bugs and how to help prevent acquiring a stomach virus.

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Viruses that can cause viral gastroenteritis include the following:


Norovirus belongs to the Caliciviridae family of viruses. It is the leading cause of vomiting, diarrhea, and foodborne illness in the United States. Evidence notes that norovirus is responsible for roughly 90% of viral gastroenteritis outbreaks and almost 50% of cases across the world.


Rotavirus is a member of the Reoviridae family of viruses. This virus most commonly affects infants and young children. However, the virus can still result in viral gastroenteritis in older children and adults, but they tend to have milder symptoms.


Adenovirus belongs to the Adenoviridae family of viruses and can cause various illnesses. These viruses typically affect the respiratory tract and can cause conditions such as the common cold. However, these viruses can also result in acute gastroenteritis.


Sapovirus also belongs to the Caliciviridae family of viruses. While it can cause viral gastroenteritis in all age groups, it is most common in children younger than 5 years of age.


Astrovirus is a member of the Astroviridae family of viruses. While these viruses can cause viral gastroenteritis in adults, they more commonly affect children. Astrovirus also frequently affects older adults and immunocompromised individuals.

The term gastroenteritis refers to irritation and inflammation of the stomach and intestines. As the name suggests, only viruses are responsible for viral gastroenteritis. However, other pathogens, such as bacteria and parasites, can result in other nonviral types of gastroenteritis.

For example, food poisoning is a type of gastroenteritis that a person may experience after consuming food containing certain bacteria. Nonviral causes of gastroenteritis can include Salmonella, Campylobacter, Escherichia coli, and Clostridioides difficile.

Additionally, certain chemicals and medications can also cause gastroenteritis.

Learn more about stomach bugs vs. food poisoning.

The duration of viral gastroenteritis symptoms may vary depending on the virus causing the condition. Typically, symptoms occur 1–2 days following infection and may last up to 10 days. The main symptoms of viral gastroenteritis include:

A common complication of viral gastroenteritis is dehydration. Symptoms of dehydration may include:

A person can acquire viral gastroenteritis by consuming foods or beverages containing viruses or touching surfaces with viruses on and touching their mouth.

Contact with stool or vomit of people with viral gastroenteritis can also cause the condition. When a person has viral gastroenteritis, the virus is present in their stool and vomit. The virus can spread through stool and vomit particles, especially if a person does not thoroughly wash their hands and then:

  • touches surfaces or objects that others may use
  • prepares food or drink
  • touches other individuals

A person does not need to have active symptoms of the infection for viruses to spread. For example, the viruses that can cause viral gastroenteritis may be present in a person’s stool before any noticeable symptoms occur.

To help prevent stomach bugs, health experts advise:

  • thoroughly washing hands with soap and water after using the bathroom and at regular intervals
  • not relying on hand sanitizer, instead using soap and water when possible
  • handling and preparing food safely, such as thoroughly cooking and washing food and sanitizing kitchen utensils and counters
  • not preparing or handling food or caring for others while sick
  • regularly cleaning and disinfecting surfaces
  • thoroughly washing clothes or linens that may have vomit or poop on them

Learn more about how to help prevent the spread of viruses.

A person experiencing viral gastroenteritis will typically recover with rest and plenty of fluids. It is important to maintain hydration by drinking water and oral rehydration solutions to help replace electrolytes.

While there is no specific medication to treat viral gastroenteritis, some over-the-counter (OTC) options may help to relieve symptoms. For example, loperamide (Imodium) and bismuth subsalicylate (Pepto Bismol) can help with symptoms of diarrhea.

It is important to note that some OTC treatments may not be safe for children. Caregivers can discuss treatment options with a doctor. Children should also continue to drink formula or breast milk if it is part of their everyday routine.

Learn what foods to eat with stomach flu.

A stomach bug, or viral gastroenteritis, refers to when a virus inflames the stomach and intestines. This irritation results in the symptoms of diarrhea and vomiting. Many different viruses can cause stomach flu. Some of the most common causative viruses include norovirus, rotavirus, adenovirus, sapovirus, and astrovirus.