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Stomach Flu or Food Poisoning: How to Spot the Difference

Symptoms like diarrhea, vomiting, or fever may indicate stomach flu or food poisoning. Learn to tell the difference.

Is it the stomach flu or food poisoning?

You feel a sickness in your stomach, your body aches, and you have a fever. You wonder how it could have happened. Was it that oddly chewy pork tenderloin you had for lunch or that fellow from yesterday’s meeting who coughed into his hand before you shook it? So, do you have a stomach bug or food poisoning?

How to tell the difference between a stomach bug or food poisoning

It can be a difficult question to tell the difference – especially since both have similar symptoms, can be transmitted similarly, and even the causes can overlap, but there are a few fundamental differences.


  • Stomach bug (also called stomach flu)
    A stomach bug is the common name for a viral gastrointestinal illness. It’s caused by a virus, most frequently the norovirus, rotavirus, and adenovirus, and affects nearly 21 million Americans each year. Typically, the virus is passed from eating contaminated food or drinking contaminated liquids; touching contaminated countertops and then touching your mouth, or even sharing utensils with an infected person.

  • Food poisoning
    Food poisoning is a more general term referring to illnesses caused by bacteria, viruses, or parasites. In fact, there over 250 foodborne diseases have been identified, and, according to the CDC, the top five common foodborne germs are norovirus, salmonella, clostridium perfringens, campylobacter, and staphylococcus (staph). However, when one refers to food poisoning, they tend to think of bacteria such as salmonella, E. coli, and staph – and they and others affect about 48 million Americans each year.

    Food poisoning is very often spread either by cross-contamination, where organisms from raw or undercooked foods pass to other foods, or by consuming raw or undercooked foods (commonly meat, dairy, and sauces) directly.You’ll notice that norovirus is listed under both because it can be transferred through food. Technically, however, it’s more accurate to say that the norovirus is a form of stomach bug or viral gastrointestinal illness.


The common symptoms of stomach bug include:

  • Diarrhea

  • Vomiting

  • Nausea

  • Stomach pain

  • Fever

  • Headache

  • Body ache

The common symptoms of food poisoning include:

  • Upset stomach

  • Stomach cramps

  • Nausea

  • Vomiting

  • Diarrhea

  • Fever

Here is where it’s most difficult to discern the difference between the two, as the symptoms are so similar. However, the key distinction is time: The symptoms of a stomach bug will take 12 to 48 hours to develop, while the symptoms of food poisoning typically develop much faster, usually with 6 hours of consuming an infected dish.

Length of illness

Another common difference between the two is the length of illness. Stomach bugs, particularly the norovirus, last around 1 to 3 days, while food poisoning rarely lasts more than a day or even a few hours.


There are no specific treatments for either a stomach bug or food poisoning. However, both may cause dehydration, in which case it’s best to drink plenty of water. It’s also best to avoid taking anti-diarrhea medication without a doctor’s approval, as it can exacerbate the illness, or even be deadly depending on the cause. Likewise, antibiotics will not treat stomach bugs because the “bug” is not a bacterial infection.

If you suspect you may be suffering from dehydration, come into a WellNow clinic for treatment.


This is where the overlap between the two is actually helpful, as you can protect yourself from both stomach bugs and food poisoning by:

  • Frequently washing your hands for at least 20 seconds after using the toilet; changing diapers; and eating, preparing, and handling food.

  • Wash your fruits and vegetables before preparation and before eating them.

  • Make sure your food is properly cooked. (Norovirus, in particular, can withstand temperatures of up to 140 degrees Fahrenheit.)

The USDA recommends the following temperatures for meat:

  • Whole cuts of pork, beef, veal, and lamb: 145°F with 3-minute resting time.

  • Ground pork, beef, veal, and lamb: 160°F

  • Poultry: 165°F

CDC Recommendations for Stomach Bugs:

  • Disinfecting surfaces that are frequently touched.

  • Removing and washing soiled clothes immediately, then tumble dry them.

  • Using gloves when encountering vomit or fecal matter.

  • Staying home if you’re sick.

CDC Recommendations for Food Poisoning:

  • Using separate cutting boards and plates for raw meats.

  • Keeping raw meats away from other foods in the refrigerator.

  • Refrigerate food within 2 hours of purchase.

  • Keeping the refrigerator temperature below 40°

  • Thawing frozen foods in the refrigerator, cold water, or the microwave – never the counter.

When to seek medical attention:

If you've experienced the symptoms listed above and are still unsure whether it’s a stomach bug, food poisoning, or any other illness, stop by a WellNow location near you. The skilled health care team at WellNow is ready to help. We're open for extended-hour care, 7 days a week.

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Information contained in this blog is for informational or educational purposes only and does not substitute professional medical advice or consultations with healthcare professionals. The content is not meant to be complete or exhaustive or to apply to any specific individual's medical condition. Always refer to the personalized information given to you by your doctor or contact us directly.