An Overview of the Stomach Flu

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Gastroenteritis is the second most common illness in the United States. Dubbed the "stomach flu," it is not caused by the influenza virus, nor does is it a respiratory illness. Rather, stomach flu is usually caused by a virus that attacks the intestinal tract and causes swelling and discomfort. It can also be caused by bacteria, spoiled or contaminated food, medications, or other more serious illnesses.

how long stomach flu symptoms last
Verywell / Cindy Chung


If you have ever had the stomach flu, you are probably well aware of the most common symptoms. Vomiting and diarrhea tend to be its calling cards, but there are other symptoms that can go along with this illness as well.

With stomach flu, you are also likely to experience:

  • Fever
  • Nausea
  • Abdominal pain
  • Fatigue/tiredness

The typical incubation period—the time between exposure and the start of symptoms—for stomach flu is usually 12 to 48 hours. The symptoms typically last one to three days. However, diarrhea can last up to 10 days in some people.

Dehydration from fluid loss can lead lead to additional symptoms and concerns such as lowered blood pressure.


The most common cause of the stomach flu in the United States is norovirus. Although many other viruses and bacteria can cause the same symptoms, norovirus is the most common culprit, as it is highly contagious and difficult to get rid of.


Most episodes of stomach flu do not require medical treatment and will go away on their own within a couple of days. Diagnosis is based on symptoms and similar cases in the community.


Medical treatment is typically not necessary for the stomach flu, but some people may become dehydrated from excessive vomiting and diarrhea.

Infants, children, older adults, and people with weakened immune systems are most likely to become dehydrated from a stomach bug. Depending on how bad it is, you may need a combination of treatments.

There are a few medications available by prescription that can help stop or decrease the vomiting. People who are severely dehydrated may need IV fluids.

It is important, though, to know the signs of severe dehydration and seek medical attention right away if you see them. Since this is the most common complication from the stomach flu, knowing what to watch for is essential. Signs of dehydration can look different in people of different ages as well.

Signs of Dehydration in Adults and Older Children

  • Infrequent urination (varies by age; for older children and adults, typically no urination for 12 hours is a problem)
  • Excessive thirst
  • Very dark urine
  • Dry skin and mouth
  • Dizziness
  • Fatigue or extreme tiredness and lethargy

Signs of Dehydration in Babies and Young Children

  • Dry mouth
  • No tears when crying
  • No wet diapers for more than three hours
  • Excessive irritability
  • Not playing/smiling for four hours or more
  • Sunken eyes or soft spot on the top of the head

Both children and adults who are dehydrated may have "skin-tenting" where the skin does not flatten back out immediately if you pinch it.

When to Seek Emergency Care

If you or your child experience any of the following, seek medical attention right away:

  • Vomiting blood
  • Large amounts of blood or mucous in the stool
  • Confusion
  • Feeling lightheaded or fainting when standing
  • Severe abdominal pain
  • Unusual sleepiness/difficulty waking (child)
  • Fever greater than 101 degrees
  • Dehydration
  • Persistent vomiting lasting two days or longer

Before you head to your doctor's office or the hospital, you can try to get rehydrated at home:

  • When you are vomiting, try not to eat or drink anything right away. Letting your stomach rest for about 15 minutes is usually helpful.
  • Then take small sips of water or an electrolyte drink (such as Pedialyte or Gatorade) every five to 10 minutes to help ensure that the stomach is not overloaded and that you do not begin vomiting again. Avoid drinking fruit juices and sodas.
  • If small sips are tolerated, slowly increase the amount you are drinking.
  • After taking nothing but fluids for several hours, try eating bland foods such as crackers, toast, and rice. Sticking with simple foods that are easy on the stomach is the best approach as long as you are only having symptoms of the stomach flu. It is important to avoid greasy and spicy foods because they will likely make the symptoms worse.

If you or your child have a fever with the stomach flu, Tylenol (acetaminophen) is the best way to treat the fever unless you have liver problems. Other fever reducers can be harder on the stomach and children under 18 should never be given aspirin.

Although there are several over-the-counter medication options to help with upset stomach and diarrhea, these should be used with caution. Pepto-Bismol (bismuth subsalicylate) should not be given to children, as salicylates have been linked to Reye syndrome. Medicines to stop diarrhea, such as Immodium (loperamide), are also not recommended for children.

As unpleasant as it is, diarrhea and vomiting are two of the ways the body uses to rid itself of the virus (or bacteria) that is making you sick. Taking medicine to stop this process can actually make the illness worse. If you are concerned about the amount that your child is vomiting and having diarrhea, talk to her pediatrician about the best treatment options.


Preventing the stomach flu is difficult because it is highly contagious. If you or someone in your life has the stomach flu, try to keep your distance. Of course, that's sometimes impractical.

Do the best you can and follow good handwashing practices. In particular, be sure to wash your hands after touching something that many others have touched (like a public doorknob) and after changing a child's diaper. You should also avoid sharing drinks and eating utensils with someone who is sick.

Hand sanitizer may not be as effective at killing norovirus, so favor washing your hands well with soap and water.

Wash linens in hot water and don't share items between sick and well family members. Look out for "unintentional sharing" too, such as placing your toothbrush in the same holder as theirs.

A Word From Verywell

Whether you call it stomach flu, a stomach bug, gastroenteritis, food poisoning, or something else, the fact is it's not pretty. The symptoms it causes are unpleasant, to say the least. Although it can be hard to avoid if someone in your home has it, knowing what to do and steps you can take to protect yourself should help.

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Article Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial policy to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Schmutz C, Bless PJ, Mäusezahl D, Jost M, Mäusezahl-feuz M. Acute gastroenteritis in primary care: a longitudinal study in the Swiss Sentinel Surveillance Network, Sentinella. Infection. 2017;45(6):811-824. PMID:28779435

  2. Hoxha T, Xhelili L, Azemi M, et al. Performance of clinical signs in the diagnosis of dehydration in children with acute gastroenteritis. Med Arch. 2015;69(1):10-2.

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