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Gastroenteritis
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Infections

Gastroenteritis

Gastroenteritis is an inflammation of the stomach and intestinal lining that typically causes vomiting and diarrhea, often referred to as the "stomach flu."

What is gastroenteritis?

Gastroenteritis is an inflammation of the lining of the stomach and intestines. While usually not serious in healthy people, it can sometimes lead to dehydration or cause severe symptoms.

What causes gastroenteritis?

There are many different causes of gastroenteritis, including:

  • Viruses
  • Bacteria
  • Parasites
  • Chemicals
  • Reactions to certain medicines and food

Viral gastroenteritis is the most common type. While some call it the "stomach flu," this is not medically correct; it is not caused by flu viruses, which are respiratory infections. When gastroenteritis is caused by consuming contaminated food or drinks, it is called food poisoning. These germs can also spread from person to person through contact with contaminated surfaces followed by touching your eyes, mouth, or nose.

What are the symptoms of gastroenteritis?

Symptoms include diarrhea, abdominal pain or cramping, nausea, vomiting, and sometimes fever. Certain groups are at higher risk for complications, including pregnant women, older adults, people with weakened immune systems, infants, and babies born prematurely.

Contact a health care provider immediately if you or a family member at high risk shows symptoms. For others, contact a provider if you experience warning signs such as:

  • For adults: Change in mental state, diarrhea lasting more than 2 days, high fever, frequent vomiting, six or more loose stools in a day, severe abdominal or rectal pain, black/tarry/bloody stools, or signs of dehydration.
  • For infants and children: Change in mental state, diarrhea lasting more than a day, any fever in infants, high fever in older children, frequent loose stools, frequent vomiting, severe abdominal or rectal pain, signs of dehydration (such as no wet diapers for 3 hours or no tears when crying), or black/tarry/bloody stools.

How is gastroenteritis diagnosed?

To diagnose gastroenteritis, your provider will perform a physical exam, ask about your symptoms, and may conduct stool tests.

What are the treatments for gastroenteritis?

Most people recover on their own with rest and plenty of fluids and electrolytes. Providers may suggest a probiotic to help shorten the duration of diarrhea. Severe cases may require medicines to control nausea or vomiting, or specific treatments like antibiotics or antiparasitic medicines depending on the cause.

Can gastroenteritis be prevented?

While not always preventable, proper hand washing, cleaning infected surfaces, and safe food preparation can help. There are also vaccines for infants to protect against rotavirus infections.

Frequently Asked Questions

Viral gastroenteritis, such as norovirus, typically has an incubation period of 12 to 48 hours and often presents with prominent vomiting and watery diarrhea. Bacterial food poisoning, such as from Salmonella or E. coli, may have a longer or shorter incubation period depending on the pathogen and is more likely to cause bloody or mucoid stools, high fever, and severe abdominal cramping. If symptoms include blood in the stool, a fever over 102°F (38.9°C), or symptoms lasting more than three days, it is more suggestive of a bacterial cause and warrants medical evaluation.
The primary goal is to replace lost fluids and electrolytes. Breast milk or formula should be continued in small, frequent amounts to avoid overwhelming the stomach. For older infants, oral rehydration solutions (ORS) like Pedialyte are preferred over plain water or sugary juices, as they provide the correct balance of salts and sugars to facilitate fluid absorption. If the infant is vomiting, pause feeding for 30 minutes and then restart with very small sips (one teaspoon every 5-10 minutes). Seek immediate medical attention if the infant shows signs of severe dehydration, such as no tears when crying, a dry mouth, or fewer than three wet diapers in 24 hours.
No, anti-diarrheal medications are generally not recommended for children or for adults with suspected bacterial infections, high fever, or bloody stools. These medications can slow gut motility, which may trap the pathogen in the intestines, prolonging the infection and potentially worsening symptoms. They may be considered for adults with uncomplicated viral gastroenteritis to reduce the frequency of bowel movements, but they should be used with caution and only after consulting a healthcare provider, especially if there is any uncertainty about the cause of the illness.
Most healthcare and public health guidelines recommend staying home until you have been symptom-free for at least 24 to 48 hours. For healthcare workers, food handlers, and childcare providers, stricter criteria often apply, such as being symptom-free for 48 hours and, in some cases, providing a negative stool test. It is crucial to practice rigorous hand hygiene with soap and water for at least 20 seconds, as alcohol-based hand sanitizers are less effective against certain viruses like norovirus. Avoid preparing food for others until you have been completely symptom-free for at least 48 hours.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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