Mark Gurarie is a freelance writer, editor, and adjunct lecturer of writing composition at George Washington University.

Suzanne Fisher, RD, founder of Fisher Nutrition Systems, has been a board-certified registered dietitian and licensed nutritionist for over 30 years.

If you’ve ever had the stomach flu, known as gastroenteritis , you’re far from alone. Infection with norovirus, the most common cause, is the second most common illness in the US. Occurring due to infection and inflammation of the intestines and stomach, typical symptoms include fever, diarrhea, abdominal pain, and vomiting.

In most cases, stomach flu resolves without medical management, and there’s no outright cure for it. Ensuring you get rest, staying hydrated, and making dietary changes are among the strategies to help you manage stomach flu. It’s important to understand the symptoms and causes of this common condition as well as what home remedies and medical approaches look like.

Stomach flu symptoms arise due to an inflammation of the tissues of your intestines and stomach (parts of the gastrointestinal tract). It arises due to infection, most often with the norovirus,a type of viral gastroenteritis. Despite being called "stomach flu," it’s not actually caused by the influenza (flu) virus virus; however, both diseases can be very contagious. As an acute condition, this illness that causes diarrhea generally affects you for a short time and resolves within a week.

Gastroenteritis tends not to be severe in healthy adults, though it can be fatal in infants, people over age 65, and those with weakened immune systems.  People who are immunocompromised (have weakened immune systems) include those who have existing health conditions, are taking certain medications that lower their immunity, or undergoing chemotherapy.

The most common symptoms of gastroenteritis are:

The most significant complication of stomach flu is dehydration as this can become dangerous, or even fatal. In adults, this can cause an array of additional signs, including:

Parents of infants should also recognize the signs their child is dehydrated. These include:

Fundamentally, stomach flu symptoms are the result of inflammation in the gastrointestinal system. This can be caused by viruses (viral gastroenteritis), bacteria, parasites, or chemicals.

Viral forms of stomach flu are highly contagious as the virus spreads through contact with an infected person’s stool or vomit. It can be picked up from direct contact with that person, contaminated food, or after touching a surface and then your mouth without washing your hands.

Most gastroenteritis cases are caused by three viruses, which are:

In the United States, most viral gastroenteritis outbreaks are due to norovirus, rotavirus, and astrovirus and occur during the winter months. This is because most spend more time indoors and in close quarters to others when it’s colder, increasing the chances of transmission.  

Certain bacterial infections can also cause stomach flu, though this type of gastroenteritis is rarer than viral types. The bacteria causing food poisoning grow on foods like meat, fruits, and vegetables, as well as other food; water and liquids can also be contaminated. Primarily, three types of bacteria cause bacterial gastroenteritis:

Gastroenteritis may also arise due to infection with microorganisms, as in giardiasis. This is an infection of the Giardia duodenalis parasite, often referred to as giardia. Following contact, these microbes reside in the intestines and pass through the feces.

Another parasite that causes gastroenteritis is Cryptosporidium, infections that lead to cryptosporidiosis , commonly known as crypto. Like giardia, this parasite survives in the intestines and spreads via contact with human or animal feces.

Lastly, exposure to certain chemicals and contaminants can cause diarrhea, vomiting, and other gastroenteritis symptoms. As with the others, transmission is often through contaminated food or drink.

When what you eat or drink is contaminated with viruses, bacteria, contaminants, or parasites, you contract food poisoning. This is a type of gastroenteritis.   

In most cases, stomach flu resolves on its own, without the need for medications or medical treatments. Healing from the condition primarily means managing the symptoms, getting rest, staying hydrated, and boosting electrolyte intake. Treating gastroenteritis primarily involves dietary restrictions, drinking water, and getting rest.

There’s much you can do to prevent the infections that cause this condition.   

Since stomach flu causes nausea and vomiting, eating and getting enough nutrients can be challenging. Making dietary changes is a cornerstone of gastroenteritis treatment.

The BRAT (bananas, rice, applesauce, and toast) diet is designed to ease the symptoms of stomach flu, diarrhea, and nausea. It consists of foods that are low in protein, fiber, and fat, which are easier to digest. These are foods that are bland and easy to chew. There is, however, limited evidence of its efficacy.

It is recommended to choose soft, low residue/low fiber foods, unseasoned lean protein sources (poultry/eggs), tea, broth, and hydration fluid, such as Pedialyte, and avoiding dairy.

It is best to start with a liquid-based diet and work up to more solid foods.

Popsicles (ice pops) and hard candies

Toast, plain pasta, or rice

Raw or dried fruits and vegetables (bananas are recommended)

Whole grain cereals or breads

Milk and dairy products, like cheeses, butter, etc.

Seeds, nuts, popcorn, and coconut

The primary focus of treatment for gastroenteritis involves ensuring you don’t become dehydrated. Central to management is fluid and electrolyte intake. This may involve:

Additionally, a provider may recommend oral rehydration therapy. This requires drinking a preformulated solution of water, bicarbonate, glucose, and sodium chloride (electrolytes) throughout the day.

One of the most important things your body needs to fight off infection is plenty of rest. Take time off of work, keep your child out of school or daycare if they're infected, and make sure you and your child is getting enough sleep. This will help strengthen the immune system and allow you time to recoup.  

Gastroenteritis is highly communicable; the viruses, bacteria, and other pathogens that cause it are often resilient and able to survive on surfaces or foods. Ways to prevent infection include:

If you’re sick, you can spread gastroenteritis by handling food. Make sure to very thoroughly wash your hands or put on rubber gloves before touching anything you’ll be eating.  

In some cases, home management of stomach flu isn’t enough to stop nausea, diarrhea, and other symptoms. You may be prescribed:

If you’re taking prescribed or OTC medications for gastroenteritis, do so with care. Be mindful of your condition and use them only as directed. Let your healthcare provider know if you’re experiencing debilitating side effects or worsening symptoms.

Gastroenteritis symptoms can be especially dangerous for certain populations, prompting a call to your provider. These include:

In addition, if an infant is not drinking or has had diarrhea for two days, you should seek immediate medical attention.

Furthermore, the following symptoms warrant medical help:

Stomach flu, or gastroenteritis , is an inflammation of the intestines and stomach that causes diarrhea, vomiting, nausea, and sometimes fever. Symptoms typically resolve within two weeks—often within one to three days—without medical treatment. Gastroenteritis symptoms can cause severe dehydration.

While this condition is often viral in origin, with most cases arising due to norovirus infection, it can also be the result of exposure to bacteria, such as E. coli, parasites like giardia, or chemicals. Stomach flu can be highly contagious. Infants and children, older people, and those with compromised immunity are more likely to develop stomach flu.

The goals of treatment for gastroenteritis are to prevent dehydration, get rest, manage symptoms, and employ a restricted diet. This may involve drinking water or drinks with electrolytes, prioritizing sleep and rest throughout recovery, and taking OTC medications, such as Imodium (loperamide) and probiotics. Signs of dehydration prompt immediate medical attention.  

Whether you’re experiencing the symptoms of stomach flu or your child or loved one, it’s important to take the condition seriously. As you go through home management by rehydrating, treating symptoms, resting, and following a restricted diet, remember to be vigilant. A careful and deliberate approach—one that’s informed and focused—will go a long way in ensuring a successful recovery.

If you’re concerned about stomach flu symptoms or are seeing signs of dehydration, don’t hesitate to call your healthcare provider or even emergency medical help.

Many types of stomach flu, or gastroenteritis, are highly contagious. The amount of time that you’re contagious depends on the specific virus or other pathogens that are causing the symptoms.

For norovirus—the most common type—you’re usually contagious anywhere from two days to two weeks after symptoms have resolved.

People with rotavirus are contagious before you feel sick, about one to two days as well as up to two weeks after recovery.

The duration of stomach flu symptoms, or gastroenteritis, depends on the underlying viral, bacterial, or parasitic infection. Most recover without medical help anywhere from a couple of days to two weeks.

With norovirus infection—the most common type—symptoms arise within two days of exposure, and last 24 to 72 hours.

Rotavirus tends to last longer, anywhere from three to eight days, and adenovirus can last up to two weeks.

To manage the diarrhea and vomiting associated with stomach flu, it’s often recommended that you stick to a restricted diet focused on bland and soft foods. Generally, you should be able to start reincorporating fruits and vegetables and getting back to normal as your symptoms subside.

Most cases of stomach flu resolve within two to three days.

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Johns Hopkins Medicine. Bacterial gastroenteritis.

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