Food Poisoning vs Stomach Flu: What’s the Difference?

When you have an upset stomach, it can be difficult to tell if you have food poisoning or stomach flu.This is because they have similar symptoms such as vomiting and diarrhea. But the reasons for these two cases are completely different.

Food poisoning occurs when you eat food contaminated with bacteria, viruses or parasites, while stomach flu (medically known as a virus Gastroenteritis) is usually caused by exposure to certain viruses. These conditions can usually be treated at home, but if symptoms become severe or dehydration develops, medical attention may be required.

This article explains the difference between food poisoning and stomach flu, as well as treatment options for each.


The symptoms of food poisoning and stomach flu overlap quite a bit, so it’s important to know the signs that are specific to each condition.

The biggest difference between the two diseases is time. For example, if you develop symptoms within a few hours of eating, you most likely have food poisoning. Stomach flu symptoms, on the other hand, usually appear within a day or two of exposure to the virus.

symptoms of food poisoning

The main symptoms of food poisoning are:

  • Vomit
  • Diarrhea (may be bloody, watery, or mucus-like)
  • nausea
  • stomach pain and cramps
  • fever
  • weakness

Symptoms of stomach flu (viral gastroenteritis)

The main symptoms of stomach flu include:

  • Vomit
  • diarrhea
  • stomach pain and cramps
  • fever
  • headache
  • Muscle pain
  • chills

when to call the doctor

Watch for symptoms of dehydration and seek medical attention if you notice any of the following:

  • vomiting or diarrhea that lasts more than 24 hours
  • blood in vomit
  • severe vomiting
  • severe abdominal pain
  • Difficulty keeping fluids down
  • Signs of severe dehydration, including dark or little urine, dry mouth, dizziness, weakness, confusion, fainting, or high fever


You can get food poisoning and stomach flu from exposure to bacteria, but in different ways.

Causes of food poisoning

Food poisoning is caused by eating food contaminated with bacteria.This is usually bacteria Escherichia coli (Escherichia coli), Staphylococcus aureusor salmonellabut it may also include viruses or parasites.

When you have food poisoning, you will notice this disease:

  • Usually happens within hours
  • Can be traced back to a specific food source
  • Affect multiple people
  • more severe symptoms than stomach flu (such as bloody diarrhea and projectile vomiting)

Causes of stomach flu

Stomach flu is an infection that attacks the intestines.It is usually caused by a virus such as Norovirus in adults or Rotavirus in children. But it can also be triggered by other viruses, bacteria, parasites or toxins.

While other illnesses are airborne, stomach flu is spread by:

  • contaminated food or drink
  • touching an infected surface
  • Person-to-person contact with an infected person
  • contact with the vomit or feces of an infected person


A medical diagnosis of food poisoning or stomach flu is not always necessary, but there are some exceptions.

If you are in a high-risk group (including the elderly, pregnant, or immunocompromised), or if your symptoms are severe and prolonged, you should contact a healthcare provider immediately for diagnosis and treatment.

Most healthy adults do not need a formal diagnosis, but it can be helpful to know this information so you can treat your symptoms appropriately and avoid spreading germs unintentionally.

Diagnosis of food poisoning

For food poisoning, many people don’t seek medical care, and if they know another person is sick from the same food or drink source, they just think it’s food poisoning. However, if you do see a health care provider for a food poisoning diagnosis, you can expect:

  • Review your symptoms
  • medical history
  • physical examination

Other tests (such as blood, urine, or stool tests) may be ordered to identify potential sources of infection. This is especially important in the context of community outbreaks.

Diagnosis of stomach flu

Most people are infected with the viruses that cause gastroenteritis because they are highly contagious and spread easily. It doesn’t always require a trip to your healthcare provider’s office, but if it does, your appointment will include:

  • Review your symptoms
  • medical history
  • physical examination
  • recent whereabouts, as you are more likely to catch the disease in crowded places like daycares or cruise ships

Testing may not be done unless there is a reason to find out the strain of the virus, such as an outbreak in a hospital setting.

A stool test can be used to diagnose rotavirus (a common virus that causes stomach flu) if needed, but this is not routine. Blood tests or imaging tests are only done if other diseases or conditions are suspected.

How common are they?

Infections such as food poisoning and stomach flu are common. An estimated 48 million people in the United States suffer from food poisoning each year, and as many as 21 million suffer from the stomach flu caused by norovirus. While many people recover quickly from these seemingly innocuous illnesses, they result in thousands of emergency room visits and hospitalizations in the United States each year.


Similar strategies are involved in the treatment of food poisoning and stomach flu. Like many viruses, treatment will focus on preventing dehydration and managing symptoms. For most people, this can usually be done effectively at home and may include the following options:

  • Stay hydrated with fluids like water or electrolyte-rich beverages
  • Add the BRAT diet (bananas, rice, apples and toast) slowly when you can control your food
  • Get enough rest to help your body heal
  • Use over-the-counter medicines such as Pepto-Bismol (Bismuth Subsalicylate) for upset stomach, Imona (loperamide) for mild diarrhea, or Tylenol (Acetaminophen) fever
  • using prescription drugs, such as Zoffran (ondansetron) or Ragland (metoclopramide) to treat symptoms of nausea and vomiting (if recommended by your healthcare provider)

In some cases of severe food poisoning, your provider may prescribe antibiotics for the infection, such as Shigellosis Or antiparasitic drugs for infections caused by parasites.

high-risk individuals

Immediate medical attention may be needed for infants, children, and people with compromised immune systems who are at high risk for dehydration from vomiting or diarrhea. Some cases of dehydration require treatment with medication or intravenous (IV) fluids.


Food poisoning isn’t usually as contagious from person to person as stomach flu, so prevention techniques for the two diseases will differ.

prevent food poisoning

Food poisoning is usually not contagious, but some forms can be spread through contact with infected bodily fluids (for example, when a person’s hands become contaminated with feces and then touch their mouth).

Although it doesn’t usually spread from person to person, you can still take steps to prevent food poisoning from happening in the first place, including:

  • Wash hands and work surfaces before, during and after food preparation.
  • Separate raw meat, poultry, seafood, and eggs from ready-to-eat foods.
  • Cook food to the proper internal temperature to kill harmful bacteria.
  • Keep the refrigerator at or below 40 degrees Fahrenheit.
  • Refrigerate leftovers within two hours of cooking.

prevent stomach flu

Stomach flu is highly contagious and spreads easily. A person can be contagious before symptoms start and for a few days after symptoms stop. In fact, bacteria can stay in your stool for up to two weeks, so you need to take extra hygiene precautions, including:

  • Wash your hands often and thoroughly with soap and water.
  • During a known outbreak of the virus, keep your hands away from your mouth and avoid shaking hands.
  • Safely handle and prepare food.
  • Clean and disinfect common surfaces.
  • Wash clothes thoroughly.
  • Stay home and away from others when you are sick.

How long should you stay at home with stomach flu?


Food poisoning and stomach flu can have similar symptoms, such as nausea and vomiting, but they are different conditions. Food poisoning is caused by food contaminated with bacteria, viruses, parasites or toxins, while stomach flu is usually caused by norovirus. Both can usually be treated at home with hydration, over-the-counter medications to relieve symptoms, and rest.

VigorTip words

Food poisoning and stomach flu are both common. It is important to protect yourself, your loved ones and your community by practicing good hygiene and making sure food is prepared and served safely. If you develop either condition, keep an eye out for signs of severe dehydration, and be sure to see a healthcare provider if you have a weakened immune system or severe or lingering symptoms.