Stomach flu (viral enteritis) is an infection in the intestines. It has an incubation period of 1 to 3 days, during which no symptoms occur. Once symptoms appear, they usually last for 1 to 2 days, although symptoms may linger for as long as 10 days.

This can be especially true for older people.

Stomach flu symptoms include:

  • diarrhea
  • vomiting
  • stomach cramps
  • loss of appetite
  • mild fever (in some cases)

In many instances, the vomiting caused by stomach flu stops within a day or two, but diarrhea can last several days longer. Toddlers and children usually stop vomiting within 24 hours of the onset of symptoms but have lingering diarrhea for another day or two.

In some instances, these symptoms may persist for up to 10 days.

Stomach flu isn’t a serious condition for most people with healthy immune systems. It can become dangerous for infants, toddlers, children, and the elderly if it leads to dehydration and isn’t treated.

What’s the difference between stomach flu, food poisoning, and seasonal flu?

Stomach flu isn’t the same thing as food poisoning, which often occurs within hours of ingesting a contaminated substance. Food poisoning has similar symptoms to stomach flu. Symptoms of food poisoning usually last for one to two days.

Stomach flu isn’t the same as seasonal flu, which causes coldlike symptoms that typically last one to two weeks.

Stomach flu can be very contagious. The amount of time you’re contagious is determined by the type of virus you have. Norovirus is the most common cause of stomach flu. People with stomach flu caused by norovirus become contagious as soon as they start to have symptoms and remain contagious for several days afterward.

Norovirus can last in stool for two weeks or longer. This makes it possible for caregivers who change diapers to become infected unless they take precautions such as immediate hand washing.

Rotavirus is the leading cause of stomach flu in infants, toddlers, and children. Stomach flu caused by rotavirus is contagious during the incubation period (one to three days) that precedes symptoms.

People infected with this virus continue to be contagious for up to two weeks after they’ve recovered.

The best home remedies for stomach flu are time, rest, and drinking fluids, once your body can keep them down.

If you can’t drink fluids, sucking on ice chips, popsicles, or sipping small amounts of liquid can help you avoid dehydration. Once you can tolerate them, water, clear broth, and sugar-free energy drinks are all good options.

For young children and babies

For young children, using an oral rehydration solution (ORS) can help avoid or treat dehydration. ORS beverages, such as Pedialyte and Enfalyte, are available without a prescription.

They can be administered slowly, over a period of three to four hours, a few teaspoons at a time. Try giving your child one to two teaspoons, every five minutes. Babies can also be given ORS liquids via a bottle.

If you’re breastfeeding, continue to offer your breast to your baby unless they’re vomiting repeatedly. Formula-fed babies can be given formula if they aren’t dehydrated and are able to keep fluids down.

If your baby has been vomiting, regardless of whether they’re breastfed, bottle-fed, or formula-fed, they should be offered small amounts of ORS liquids via bottle, 15 to 20 minutes after vomiting.

Don’t give babies or children anti-diarrheal medication unless their doctor recommends it. These medications may make it harder for them to eliminate the virus from their systems.

For adults and older children

Adults and older children typically experience diminished appetite while sick with stomach flu.

Even if you feel hungry, avoid eating too much too soon. You shouldn’t eat solid food at all while you’re actively vomiting.

Once you start to feel better and your nausea and vomiting stop, opt for foods that are easy to digest. That can help you avoid additional stomach irritation.

A bland diet, such as the BRAT diet is a good one to follow while you recover. The starchy, low-fiber foods in the BRAT diet, which include bananas, rice, applesauce, and toast, help firm up stool and reduce diarrhea.

Choose a low-fiber bread (such as white bread, without butter) and sugar-free applesauce. As you start to feel better, you can add other easy-to-digest foods such as plain baked potatoes and plain crackers.

While you’re recovering, avoid things that might irritate your stomach or that might trigger additional bouts of nausea or diarrhea, including:

  • fatty or greasy foods
  • spicy foods
  • high-fiber foods
  • caffeinated beverages
  • hard-to-digest foods, such as beef
  • dairy products
  • foods high in sugar

Stomach flu usually clears up on its own within a few days but sometimes requires a doctor’s care.

Infants and babies with stomach flu should be seen by a doctor if they are running a fever or vomit for longer than a few hours. If your baby seems dehydrated, call the doctor immediately. Signs of dehydration in babies include:

Reasons to call the doctor for toddlers and children include:

  • distended stomach
  • abdominal pain
  • severe, explosive diarrhea
  • severe vomiting
  • fever that doesn’t respond to treatment, lasts more than 24 hours, or is over 103°F (39.4°C)
  • dehydration or infrequent urination
  • blood in vomit or stool

Adults and the elderly should seek medical treatment if their symptoms are severe and last more than three days. Blood in vomit or stool also warrants a doctor’s care. If you’re unable to rehydrate, you should also seek medical help immediately.

Signs of dehydration in adults include:

  • no perspiration and dry skin
  • little or no urination
  • dark urine
  • sunken eyes
  • confusion
  • rapid heartbeat or breathing

The stomach flu typically resolves on its own within a few days. The most serious concern, especially for infants, toddlers, children, and the elderly, is dehydration. If you’re unable to rehydrate at home, call your doctor.