Stomach Flu: What is It, How Long Does It Last, and What Are the Treatment Options

Published June 29th, 2022 by Chris Riley
Fact Checked by
Jacqueline Hensler
Medically Reviewed:
Dr. Angel Rivera

Stomach Flu 101 | Symptoms | Most at Risk | Causes | Treatment Options

The stomach flu is a viral infection that affects the gastrointestinal tract and is also known as gastroenteritis.

The most common symptoms of stomach flu are diarrhea, vomiting, and abdominal cramps but, in some cases, you may also have a fever or headache.

The stomach flu is highly contagious and can be spread through contact with contaminated surfaces or objects, or by eating or drinking contaminated food or water.

It can also be spread by coming into contact with the respiratory droplets of an infected person.

In this article, we will discuss everything you need to know about stomach flu, how to treat it, and how to prevent getting it.

What is stomach flu?

Stomach flu, also called viral gastroenteritis or "the stomach bug", is a contagious infection that causes the inflammation of your stomach and intestines and it is not related to the influenza virus despite its misleading name.

The symptoms may center around your stomach or abdomen but the stomach flu can also affect your small intestines and colon too.

You usually can recover from the stomach flu, however, it can be fatal for at-risk individuals such as infants, the elderly, or if you have an underlying condition that causes you to be immunocompromised.

There is no cure for the stomach flu so your best option is to focus on prevention.

woman in pain on couch with stomach flu

What are the symptoms of stomach flu?

The most common stomach flu symptoms include:

  • Watery diarrhea and in rare cases bloody diarrhea although this is usually a sign of other medical conditions
  • Frequent bowel movements
  • Nausea
  • Vomiting
  • Abdominal pain or stomach cramps
  • Fever
  • Headache
  • Muscle aches
  • Fatigue

You may also experience a loss of appetite, dehydration due to vomiting and diarrhea, and weight loss.

If you experience these symptoms for more than a couple of days, it is best to see your doctor as you may be dehydrated.

Symptoms of gastroenteritis will usually appear within one to three days after you become infected and will normally last for one to two days although symptoms can last for up to two weeks.

Stomach Flu In children

Infants and children can also experience other symptoms such as:

  • Fussiness or irritability
  • Looking as if they are in pain
  • Lack of energy or lethargy
  • Dry mouth and throat
  • Decreased urination that is noticeable by not having wet diapers for over six hours
  • Crying more than usual but tears may not come out
  • Bloody diarrhea

If your child is displaying these symptoms and signs of dehydration, it is important to seek medical attention.

Severe dehydration is the most common complication associated with stomach flu and it can be deadly for infants and young children.

Who is most at risk for the stomach flu?

While anyone can get the stomach flu, you may be more at risk than others. If you live in a communal living space you are at the most risk and these spaces include:

  • Dormitories
  • Hospitals wards
  • Prisons
  • Daycares
  • Camps
  • Cruise ships
  • Military barracks or living quarters
  • Nursing homes

You are also more likely to get the stomach flu if you travel to less developed countries because of the lack of access to clean water and sanitation.

If you have a weakened immune system, you are also at an increased risk for stomach flu as well.

What causes the stomach flu?

The stomach flu is usually caused by a virus that is spread when you drink water or eat food that has been contaminated with the virus.

You can also get the virus by sharing unwashed utensils, food, or even towels with someone who has it.

Eating raw or undercooked shellfish such as oysters or clams can also cause gastroenteritis.

However, most cases arise due to someone who handles your food or drink not washing their hands after having gone to the bathroom.

The most common viruses that cause stomach flu include:

Norovirus

Norovirus infections are the most common type of virus that causes gastroenteritis and it is highly contagious.

They are found in contaminated food or water and can also be spread through contact with a sick person who already has it. Symptoms usually appear within 12-48 hours after you have been infected.

Rotavirus

Rotaviruses are the most common type of virus that affects infants and children and it is highly contagious.

It is found in contaminated food or water and can also be spread through contact with an infected person.

Infants and young children often get it by touching a contaminated surface and putting their fingers in their mouths or by putting a contaminated surface in their mouths.

If you are an adult, you can still get rotavirus; however, you most likely will not show any symptoms but can still spread the virus.

There are now vaccines available for the rotavirus in the United States and other countries which can help prevent gastroenteritis caused by the rotavirus in infants and children.

The symptoms usually last from three days up to a week in children and infants.

Adenovirus

Adenoviruses are found in contaminated food or water and can also be spread through contact with an infected person.

They typically affect children two years old and under and can also be spread by touching contaminated surfaces and then touching your eyes, nose, or mouth.

How is stomach flu diagnosed?

There is no one test that can diagnose stomach flu. Your doctor will ask you about your symptoms and how long you have had them.

They will also ask if you have been around anyone who has been sick, if you have recently traveled, or take note if there are similar cases in your immediate community (for example, in your dormitory or nursing home).

A physical exam will be done and your doctor may order a stool sample to test for the presence of the virus.

What are the treatment options for stomach flu?

There is no one specific treatment for stomach flu and typically you will recover on your own within a few days. However, there are some things you can do to help ease your symptoms:

  • Drink plenty of fluids to avoid dehydration and drinking sports drinks can help replace electrolytes as can drinking an oral rehydration solution such as Pedialyte
  • Get rest
  • Take over-the-counter medications such as ibuprofen or acetaminophen to help with pain and fever
  • Take over-the-counter medications for diarrhea such as Immodium A-D or Pepto-Bismol
  • Avoid dairy, caffeine, and alcohol
  • Eat small, frequent meals that are easy to digest
  • Stay away from foods that are high in fat or spicy foods
  • If you vomit, eat bland foods such as crackers, soup, oatmeal, bananas, and rice, and after vomiting wait at least an hour before trying to drink fluids again
  • Start with small sips of water or fluids and gradually increase how much you are drinking

If your infant or child has gastroenteritis you can do the following:

  • Give them plenty of fluids to avoid dehydration but not plain water as it can be difficult for a child's stomach, you can give breast milk, formula, or an electrolyte solution such as Pedialyte but avoid giving your child apple juice as it can make diarrhea worse
  • If your child is old enough, give them over-the-counter medications for pain and fever
  • Avoid giving your child sugary or fatty foods
  • Give your child plenty of rest
  • Avoid antidiarrheal medications unless advised by their doctor
  • Once hydrated, return your child to their normal diet and solid foods if they are old enough

What are the complications of gastroenteritis?

Gastroenteritis can lead to dehydration which can cause hospitalization, especially in young children and if you are immunocompromised or elderly.

Drinking fluids to replace any water lost due to vomiting or diarrhea is the best way to avoid dehydration.

If you are unable to keep liquids down, seek medical help as you may need fluids through an IV.

When do I need to see a doctor?

Adults

You need to see your doctor if you have bloody stool, persistent vomiting or diarrhea for more than two days, severe abdominal pain, if you are unable to keep water or liquids down for 24 hours, if you have blood in your vomit or stool, or if you have a high fever of over 104°F (40°C).

If you are dehydrated, your doctor will give you fluids through an IV. You also need to see your doctor if you are pregnant and have gastroenteritis.

Children

Take your child to see their doctor if they have had diarrhea for more than 24 hours, have blood in their vomit or stool, if they vomit for over 24 hours, have not had a wet diaper or urinated in over six hours, are dehydrated (dry mouth, no tears when crying, sunken eyes), has a fever of over 102°F (38.9°C), is lethargic or irritable, has a soft spot on top of their head, or has severe abdominal pain.

If your child is under the age of 12 weeks and has a fever you always need to take them to see their doctor as they may have a serious infection.

Can stomach flu be prevented?

Yes, there are some things you can do to help prevent getting or spreading stomach flu such as:

  • Wash your hands often with soap and water for at least 20 seconds, especially after going to the bathroom, before eating, and after blowing your nose, coughing, or sneezing
  • Avoid close contact with people who are sick
  • Stay home when you are sick
  • Clean and disinfect surfaces that may be contaminated with the virus
  • Cover your mouth and nose with your elbow, sleeve, or a tissue when you cough or sneeze then throw the tissue in the trash
  • Make sure your child gets the rotavirus gastroenteritis vaccine
  • Use separate towels in the bathroom from your housemates and use separate dishes and utensils if possible
  • Do not touch the laundry of someone sick with gastroenteritis or use gloves to handle the laundry if you must touch it
  • Make sure any daycare or child care center has a separate room for changing diapers and that it is not in the same room as where food is prepared
  • When preparing food, wash all vegetables and be certain to cook any shellfish thoroughly, and do not prepare food for others if you have gastroenteritis

If you travel abroad to an underdeveloped country only drink bottled water and do not drink the water contaminated drinking water from the faucet or ice cubes made from faucet water, brush your teeth with bottled water, avoid raw vegetables, fruits, and shellfish, and also avoid undercooked proteins such as meat or seafood.

Prevention is especially important for young children, the elderly, and those with weakened immune systems.

Summary

Stomach flu is a virus that can cause a number of symptoms including vomiting and diarrhea and it is common in both adults and children.

The stomach flu is contagious and is often passed through contact with contaminated surfaces or close contact with someone who is sick.

The best way to prevent the stomach flu is by following the list above and, if visiting an underdeveloped country, avoid any contaminated water from the faucet and raw or undercooked foods.

If you have any more questions or believe you may have gastroenteritis, please consult with your doctor or health care professional.

References, Studies, and sources:

Cleveland Clinic 

Mayo Clinic 

WebMD

CDC

Johns Hopkins Medicine 

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