Young woman laying on couch with hand on stomach and on forehead

Viral gastroenteritis is the medical term for what we call a stomach bug or stomach flu. It’s an inflammation of the stomach and intestines caused by a viral infection.

A more common cause of stomach distress is food poisoning, which does have a dramatic, secret agent kind of sound to it. It just means that something got into your food (accidentally!) that has made you sick. As many as 48 million people experience food poisoning each year.

Let’s take a look at the similarities and differences between the stomach bug and food poisoning.

Stomach Bug:

Incubation period: 24-72 hours after exposure to the virus


  • diarrhea
  • stomach or intestinal cramps
  • nausea
  • vomiting
  • low-grade fever
  • weight loss
  • joint aches
  • muscle aches
  • thirst
  • headache or dizziness

It’s a Virus – Not the Flu

In the US, the norovirus is the most common cause of a stomach infection that attacks the digestive system. Though we call it the stomach “flu,” it is not related to the influenza virus. The norovirus is very contagious and can spread quickly through families, nursery schools, cruise ships, anywhere people are eating together, using the same bathrooms, and touching surfaces. This is why caregivers have to be especially careful to wash their hands. 

The stomach flu can resolve within a couple of days, but symptoms sometimes continue for a week or more.

Symptoms of Food Poisoning

Typical symptoms of food poisoning include:

  • stomach or intestinal cramping
  • fatigue
  • diarrhea (can be bloody)
  • fever
  • chills
  • muscle aches
  • headaches
  • sweating
  • thirst
  • general malaise
  • vomiting

In severe cases, you can have:

  • bloody stools
  • severe abdominal cramping
  • shock
  • loss of consciousness

Timing is Important When Solving This Mystery

As you can see, food poisoning often causes similar symptoms as a stomach virus, so it can be hard to know what is going on. One important clue is that food poisoning usually comes on quickly – within 4-6 hours of your eating the contaminated food you feel really terrible and usually vomit. The stomach virus comes on more slowly with symptoms worsening over a day. 

Food poisoning occurs when food is contaminated by bacteria, viruses, or parasites. The top seven causes of food poisoning are Salmonella, Listeria, Staphylococcus, Trichinosis, E. coli, Campylobacter, Clostridium.

Foods with a higher risk of contamination:

  • Raw and cooked seafood
  • Precooked deli meats
  • Premixed raw vegetables
  • Unpasteurized milk
  • Soft cheeses and soft-serve ice cream
  • Salad greens
  • Eggs 
  • Undercooked poultry

I had a very bad case of Campylobacter once. It turns out, the barbeque restaurant was using the same tongs to handle uncooked chicken as the cooked food they were going to serve. I was sick for weeks and became so dehydrated I need 2 liters of fluids. It was not fun.

I’ve also cared for children in the ICU who had severe E. coli infections that led to kidney infections and septic shock. These food borne illnesses are no joke.

Cases do rise in summer as warm weather encourages the growth of bacteria. Also, as people barbeque and eat outdoors there is more of a risk of undercooked meat, food sitting out too long, and greens not being thoroughly washed.  

Botulism is Rare

One form of possibly fatal poisoning is the infamous botulism. Although it is extremely rare in the US it most often occurs in home-canned foods. It can be fatal if people aren’t treated promptly. The bacterium called Clostridium botulinum causes botulism, producing toxins that affect the nervous system. Botulism can cause blurred vision, drooping eyelids, slurred speech, and other neuromuscular symptoms. 

Differences Between the Two

  • Bloody diarrhea is more likely to be a symptom of food poisoning.
  • Projectile vomiting and stomach cramps are often caused by the norovirus, a type of stomach virus.
  • Stomach viruses take longer to develop but usually go away in about 24 to 28 hours after symptoms begin. Food poisoning often lasts longer.
  • Food poisoning usually affects more than one person and can often be traced to a particular source.
  • A stomach virus is more likely to cause a fever, headache, and stomach pain.

If you do contract either one of these unpleasant illnesses, staying hydrated is extra important. Having diarrhea and vomiting are extremely dehydrating. Sipping water, sports drinks with electrolytes, juice, or clear broth, will help you replace those lost fluids. 

If you’ve been vomiting or unable to eat for 8 hours and things are not improving, then do call your healthcare provider or head to an Urgent Care center.

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