Stomach Flu

Also known as food poisoning or viral gastroenteritis

Viral gastroenteritis—dubbed the "stomach flu"—is the second most common illness in the United States. It is not caused by the influenza virus, and it is not a respiratory illness. Instead, the stomach flu is caused by a contagious virus (frequently norovirus or rotavirus) that attacks the intestinal tract and causes inflammation, vomiting, and diarrhea.

Many people don’t wind up seeing a doctor for the stomach flu since symptoms usually pass on their own. However, if your symptoms are severe or last longer than a few days, make an appointment to see your healthcare provider. In addition, infants, children, and people with compromised immune systems, who are most at risk for dehydration, may require immediate medical treatment. 

Frequently Asked Questions

  • How long does stomach flu last?

    Symptom onset and duration depend on the virus causing your infection. For example, with norovirus—one of the most common causes of stomach flu—the typical time between exposure and the start of symptoms is about 12 to 48 hours. Symptoms of norovirus typically last one to three days, but diarrhea and intestinal discomfort can linger for up to 10 days. 

  • How is stomach flu treated?

    In most cases, stomach flu doesn’t need to be treated by a physician. Home remedies, like getting plenty of fluids and eating a bland diet, can usually treat symptoms until the illness passes in otherwise healthy adults. Infants, children, and people who have a digestive disease or another serious illness should seek medical treatment to avoid complications.

  • What should you eat when you have the stomach flu?

    You may not be able to eat when you’re in the initial stages of stomach flu since nausea and vomiting are common symptoms. When you’re able to keep fluids down, try ingesting clear liquids like water and chicken or vegetable broth. When you’re ready to try solid foods, start with small portions of bland, easily digestible, yet appealing food until your digestive system returns to normal.

  • How long is the stomach flu contagious?

    Viral gastroenteritis can be caused by several different viruses. The two most common are norovirus and rotavirus. With norovirus, you are contagious as soon as your symptoms start. You are still contagious for three days after you recover and could spread the virus for up to two weeks. With rotavirus, you are contagious before symptoms appear and for two weeks after you recover.

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Page Sources
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  1. Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention. Updated norovirus outbreak management and disease prevention guidelines. MMWR Recomm Rep. 2011 Mar 4;60(RR-3):1-18.

  2. Lee RM, Lessler J, Lee RA, Rudolph KE, Reich NG, Perl TM, Cummings DA. Incubation periods of viral gastroenteritis: a systematic review. BMC Infect Dis. 2013 Sep 25;13:446. doi: 10.1186/1471-2334-13-446

  3. Mori A, Enweluzo C, Grier D, Badireddy M. Eosinophilic gastroenteritis: review of a rare and treatable disease of the gastrointestinal tract. Case Rep Gastroenterol. 2013;7:293-298. doi:10.1159/000354147