What is the Stomach Flu?

What is the Stomach Flu?

Stomach flu, or viral gastroenteritis, is an infection of the stomach and intestine. Many types of viruses can cause stomach irritation, but influenza (the flu) is not one of them. Influenza affects the respiratory system, while gastroenteritis affects the digestive system.

Stomach flu is very common, with millions of people experiencing the condition in the U.S. every year.

Food poisoning vs. stomach flu

While they may present with similar symptoms, stomach flu differs from food poisoning because it is caused by a virus passed from person to person. Food poisoning is caused by food or water that is contaminated with bacteria due to improper storage or cooking.

Symptoms of the stomach flu generally appear about 24 to 48 hours after a person is exposed to the virus. In comparison, food poisoning symptoms can appear as quickly as two hours after eating the contaminated food.

Signs & Symptoms of the Stomach Flu


Viral gastroenteritis causes symptoms affecting the digestive system, including:

The gastrointestinal experts at NewYork-Presbyterian can identify stomach flu symptoms and administer appropriate treatment.

What Causes Stomach Flu?


Stomach flu can be caused by several types of viruses and are contracted through contact with another person who has the virus. This commonly occurs by sharing food or utensils with an infected person or being in a small, enclosed space with an infected person.

Types of viruses that cause viral gastroenteritis include:

  • Norovirus (the most common cause of stomach flu)
  • Adenovirus
  • Astrovirus
  • Rotavirus

Risk Factors

Risk Factors

Anyone can contract the stomach flu, but some groups are more likely to contract the condition. These include:

  • Infants and young children: children’s immune systems are not yet mature, so they are at higher risk of contracting viruses
  • Older people: immune systems of older adults tend to become less efficient later in life
    Those with a suppressed immune system: if your immune system is compromised by an underlying condition or medication you are taking, you’re at higher risk of contracting a virus
  • People living in close quarters: living in a dormitory, nursing home, or another place where you come into close contact with others puts you at a higher risk of coming into contact with a person infected with stomach flu



The main complication of viral gastroenteritis is dehydration. A severe loss of body fluid and dehydration can be caused by excessive vomiting and diarrhea — both stomach flu symptoms.

Most times, you should be able to drink enough liquid to replace fluids lost during a stomach flu, but in some cases, severe dehydration may require hospitalization.

Stomach Flu Prevention


While it is impossible to prevent stomach flu completely, there are ways to limit the likelihood of becoming infected with a virus. These steps include:

  • Washing hands frequently and thoroughly
  • Disinfect surfaces
  • Avoid contact with infected persons
  • Avoid sharing utensils, towels, and other personal items
  • Prepare food safely and avoid preparing food if you are sick
Get Care

Trust NewYork-Presbyterian for Stomach Flu Care

If you are concerned you may have the stomach flu or other digestive and kidney diseases, the experts at NewYork-Presbyterian can help get you the treatment you need. Our physicians can identify your main symptoms and determine the cause of your condition, ensuring you receive the proper care.