Stomach Flu (Viral Gastroenteritis)

stomach flu, viral gastroenteritis

Key Takeaways

  • Viral gastroenteritis is a GI condition that involves the inflammation of the gastrointestinal tract’s inner lining.
  • This condition can be caused by rotavirus, norovirus, or adenovirus.
  • Babies can receive a rotavirus vaccination.
  • Viral gastroenteritis symptoms include nausea, vomiting, and diarrhea.
  • Dehydration caused by vomiting or diarrhea is the most serious complication.
  • Medical attention is only required if diarrhea or vomiting persists longer than a few days, or if dehydration becomes severe.


Most commonly known as the stomach flu, viral gastroenteritis is an infection that affects both the stomach and intestines.

Caused by a virus, symptoms may include diarrhea, abdominal cramps, nausea, and vomiting. Note that this illness may also be called a stomach bug, although some “bugs” are actually caused by bacteria or a parasite, not a virus. 

Viral gastroenteritis is, in fact, incredibly common worldwide, making it nearly impossible to determine how many suffer from it each year. Many different viruses may be to blame, and few patients are tested in clinics – two additional challenges to counting how many people suffer from the stomach flu. Experts estimate that norovirus is the most common culprit though, likely infecting about 685 million people each year.



There are several viruses known to cause gastroenteritis. These can live for long periods outside of the body and can be found in the vomit and diarrhea of those infected. The virus spreads to objects that infected people touch, especially if they don’t wash their hands after using the bathroom, or if they work with food.  Sewage contamination of the water supply can also spread viral gastroenteritis. Keep in mind that, while it is sometimes called the "stomach flu," the seasonal influenza virus does not cause it.

These are some of the most common viruses that cause gastroenteritis:

  • Rotavirus
    Most commonly infecting infants (3 to 15 months old), rotavirus produces symptoms lasting about 3 to 7 days. Rotavirus is most common in the fall and winter months.
  • Norovirus
    The most common cause of adult infections, norovirus virus is typically associated with outbreaks on cruise ships. Symptoms last from 1 to 3 days and can occur any time of the year.
  • Adenovirus
    Another virus that may spread year-round is adenovirus. It typically infects children under age 2, resulting in symptoms for 5 to 12 days.

Note: Many other viruses can also cause viral gastroenteritis.


  • Contaminated foods, drinks and surfaces: People can become infected by eating or drinking contaminated foods or beverages, or by touching contaminated surfaces and then touching their mouth. Food (especially shellfish) and water may be contaminated by sewage.


  • Abdominal pain and cramping
  • Body aches
  • Chills
  • Diarrhea
  • Fever
  • Fatigue
  • Headaches
  • Loss of appetite
  • Nausea and vomiting
  • Swollen lymph nodes


The most common complication of the stomach flu is dehydration. It occurs when you lose too many fluids and electrolytes due to frequent diarrhea or vomiting. People with weaker immune systems, particularly children, are more likely to experience dehydration – and in serious instances, it can become quite dangerous. Here at Charleston GI, our gastroenterologists recommend watching carefully or these signs of dehydration:

  • Thirst
  • Lack of urine or dark-colored urine
  • Hard or dry bowel movements
  • Weakness 
  • Sunken eyes
  • Crying without tears
  • Dehydration headache
  • Dry lips or tongue


Most cases of the stomach flu progress through these stages:

  1. Exposure: Because symptoms take time to develop, you may not hear about an outbreak until after you’ve been exposed to the virus.
  2. Incubation: Once you’ve become infected, the virus will replicate inside your body. Once it has replicated enough to alert your immune system, you will begin to experience symptoms. The incubation period is typically a few days, depending on the virus.
  3. Acute infection: Since viral gastroenteritis is an acute infection, symptoms come on suddenly and don’t usually last more than a few days. When your immune system recognizes the threat, it triggers an inflammatory response. This causes symptoms until the virus is cleared. 
  4. Recovery: When your immune system has defeated the virus, symptoms will stop and your health will improve. Keep in mind that you may continue to shed the virus in your stool for a few days. Because you are still contagious at that point, be sure to wash your hands diligently.


Contact a healthcare provider you’re suffering:

  • Symptoms have not improved after 4 days.
  • High fever (above 102 degrees Fahrenheit or 39 degrees Celsius) for 4 days.
  • Unable to pee or poop for 2 days.
  • Signs of dehydration.
  • Blood stool.
  • Severe abdominal pain.


Your gastroenterologist will diagnose the stomach flu based on your symptoms, but without a lab test, they will not be able to tell which virus you’ve been infected with. Most of the time, however, it is not necessary to know because no medication is needed.


Our GI doctors recommend resting, staying hydrated, and eating what you can. The most important thing is to let your immune system do its job! In rare cases of severe dehydration, IV (intravenous) fluids may be required.

Treatment includes:

  • Drinking plenty of light fluids such as water, ice chips, fruit juice, and broth. In cases of extreme dehydration, sugary sports drinks are not recommended. 
  • Avoiding drinks with milk, caffeine, and alcohol.
  • When symptoms begin to ease, try to consume bland foods that are easy to digest.
  • Rehydrate small children using oral rehydration solutions.

If you need help with the flu, schedule an appointment with Charleston GI today! Open 5 days a week, no referral needed!


  • Broths (ex. canned or packaged soups)
  • Caffeinated drinks
  • Candy
  • Chocolate
  • Dried fruits (ex. fruits canned in syrup)
  • Fried foods (ex. High fatty foods like potato chips, french fries, pastries etc.)
  • Fruit juices that are heavy in sugar
  • Ice cream, sherbet and popsicles
  • Jellies (ex. Jell-O)
  • Sports drinks (ex. Gatorade, Vitamin Water etc)
  • Soft or carbonated drinks
  • Sweet cereals
  • Very spicy foods


  • Bread 
  • Cooked vegetables
  • Eggs
  • Fresh fruits or fruits canned in their own juice
  • Lean meats (low fat)
  • Cooked fish (low fat)
  • Pastas
  • Rice
  • Sugar-free cereals

Following foods are ok if your digestive system can tolerate them and/or if they are lactose free:

  • Low fat cheese
  • Low fat yogurt
  • Milk
  • Probiotic (some studies show that probiotics can help reduce the intensity or duration of diarrhea)

For food recommendation, it is best to consult your GI specialist or PCP directly for further information. 


Good hygiene helps reduce your risk of contracting viral gastroenteritis – or spreading it to others. Some healthy hygiene practices include the following:

  • Handwashing: Practicing proper handwashing technique is especially important after using the restroom or changing a diaper. It is also crucial before handling food.
  • Cleaning: Wash and disinfect all surfaces or materials that you or the infected person have come into contact with. Use bleach and water (up to 25 tablespoons per gallon) as a disinfecting agent and utilize the high heat setting on your washing machine to clean bed linens and clothes.
  • Safe food handling: Food may be contaminated with stomach flu viruses, bacteria or other organisms. Safe food prep can help reduce this risk. 



What helps stomach flu go away faster?

Some research suggests that taking probiotics may help stomach flu symptoms go away faster. Probiotic supplements add helpful bacteria to your GI tract – an important part of maintaining a strong immune system. Ask your gastroenterologist if probiotics might help you.

How long does it take to recover from a stomach flu?

Symptoms often improve within a few days, but if they persist, contact your Charleston GI doctor. You may be suffering from another condition. Those with weaker immune systems may need treatment for dehydration as well.

When can I return to work or school after having the stomach flu?

If you can, stay isolated for two days after symptoms have stopped. You are most contagious during this time period. Even though your immune system has overcome the infection, you’ll still shed the live virus in your stool and could potentially infect someone else.

What does getting a stomach flu feel like?

In most cases, symptoms like vomiting and diarrhea are unexpected and come on suddenly. Symptoms occur one to two days after exposure but don’t often last more than a few days. 

What should you eat when you have stomach flu?

What you eat won’t improve stomach flu, but it can worsen symptoms. Fatty or sugary foods, beverages with caffeine, and dairy milk should be avoided. Once nausea begins to subside, try to eat easy-to-digest foods like fruit juice popsicles, broths and salted crackers. 

Can a doctor treat severe stomach flu symptoms or complications?

Yes, your GI doctor can treat dehydration using IV fluids or prescribe medications to reduce vomiting or diarrhea (adults only). 

How common is stomach flu?

Viral gastroenteritis is extremely common worldwide, making it tricky to estimate exactly how many cases occur each year. Experts estimate that norovirus, the most common cause, infects about 685 million people annually.

Why is viral gastroenteritis called “stomach flu?”

It’s not clear how the nickname came to be, or why many refer to viral gastroenteritis as the stomach flu. Both conditions tend to circulate during the same season, but it’s important to remember that viral gastroenteritis is not related to influenza.


To learn more about treatment for GI tract issues in Charleston, SC, get in touch today! Charleston Gastroenterology is committed to a higher standard of caring – and we provide a range of medical treatments to help you feel your best.

If you are experiencing GI tract symptoms or pains, schedule your appointment today! No referral needed.