Symptoms of the Stomach Flu

In This Article

Viral gastroenteritis, commonly known as the stomach flu or stomach bug, is a highly contagious short-term illness that causes vomiting and diarrhea.

The stomach flu is typically caused by a virus, such as norovirus or rotavirus. Despite its nickname, it is not an influenza infection. Although influenza may sometimes cause gastrointestinal symptoms, the flu is primarily a respiratory illness. Getting a flu shot will not protect against the stomach flu.

Frequent Symptoms

Typically, the stomach flu is a "self-limiting" illness, which means it will go away on its own after a few days.

In some cases, bacterial infections may hang on longer and need to be treated with antibiotics. However, even this is uncommon. Bacterial causes of stomach flu such as salmonella and e. Coli often go away on their own as well. 

Symptoms of stomach flu may include:

  • Vomiting
  • Abdominal pain
  • Diarrhea
  • Nausea
  • Fever
  • Chills
  • Weakness
  • Muscle Pain
  • Weight Loss
  • Decreased appetite

Depending on what is causing your illness, you could experience other symptoms as well. It's important to know when you should see a doctor for vomiting and diarrhea.

If you see blood or something that looks like black tar, contact your healthcare provider right away. 

Serious Symptoms

Excessive vomiting and diarrhea can lead to dehydration. Infants, children, older adults, and people with weakened immune systems are most at risk of dehydrated from a stomach bug.

The signs of severe dehydration include infrequent urination, with no urination for 12 hours a cause for concern, excessive thirst, very dark urine, dry skin and mouth, dizziness, fatigue or extreme tiredness and lethargy.

Additional symptoms in babies and small children include excessive irritability and inability to smile or play, no wet diapers for more than three hours, no tears when crying, and sunken eyes or soft spot.

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 See a Doctor

If you have any symptoms of dehydration, call your doctor. 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.

In addition, if you have any of these additional symptoms, seek medical attention right away.

  • Vomiting blood
  • Large amounts of blood or mucus in the stool
  • Confusion
  • Feeling lightheaded or fainting when standing
  • Severe abdominal pain
  • A child who is unusually sleepy or difficult to wake up
  • Accompanied by a fever greater than 101 degrees (call your doctor)
  • Dehydration
  • Persistent vomiting lasting 2 days or longer

A Word From Verywell

If you find yourself dealing with symptoms of the stomach flu, make sure you stay hydrated but don't try to drink too much too quickly. Overdoing it with fluids can cause more vomiting and create a vicious cycle. If you are just experiencing diarrhea, make sure you eat bland foods that won't cause too much stomach discomfort. 

There is a debate about whether the BRAT diet (bananas, rice, applesauce, and toast) is really helpful, but it certainly can't hurt, as long as you limit your intake of these foods to just while you are feeling ill. The concern is that people continue to eat this way after they have recovered, which results in a limited intake of proper nutrients that your body needs. 

Be sure to avoid foods that are spicy, fatty, or greasy while you have the stomach flu and don't drink alcohol or caffeine. Electrolyte drinks such as Gatorade or Pedialyte are the best way to rehydrate but regular water works too. 

Stomach viruses are highly contagious, so washing your hands and cleaning is essential. It is really hard to avoid passing it among family members living in the same house, but cleaning as much as possible will minimize the chances. 

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Article Sources

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    doi:10.1016/S0140-6736(18)31128-0

  2. Cleveland Clinic. Gastroenteritis (Stomach Flu) Symptoms & More. https://my.clevelandclinic.org/health/diseases/12418-gastroenteritis.

  3. Stuempfig ND. Viral Gastroenteritis. StatPearls [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK518995/#_NBK518995_pubdet_. Published March 15, 2019.

  4. Churgay CA, Aftab Z. Gastroenteritis in Children: Part I. Diagnosis. American Family Physician. https://www.aafp.org/afp/2012/0601/p1059.html. Published June 1, 2012.

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Additional Reading

  • "Viral Gastroenteritis." PubMed Health 12 Apr 10. US Library of Medicine. National Institutes of Health. 25 Feb 11.
  • Mayo Clinic. Viral Gastroenteritis. https://www.mayoclinic.org/diseases-conditions/viral-gastroenteritis/diagnosis-treatment/drc-20378852

  • NIH. Viral Gastroenteritis. www.niddk.nih.gov/health-information/health-topics/digestive-diseases/viral-gastroenteritis/Pages/facts.aspx.