Telling the difference in symptoms between food poisoning and a stomach bug can be tough. That’s because both conditions bring on nausea, vomiting, and those dreaded stomach cramps. But knowing exactly what you have can help you manage symptoms and avoid a repeat run-in with either condition. Let’s break down the clues that can help you tell them apart and how to recover faster when you’re hugging the porcelain throne.
Causes and symptoms of food poisoning
Food poisoning occurs when you consume food (or drinks) tainted by bacteria, fungi, parasites, or viruses—or even their toxic byproducts, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Contamination can happen anytime, from harvest to prep, and usually strikes when food isn’t:
- Fresh
- Washed well
- Handled in a sanitary way
- Cooked to a safe internal temperature
- Held at proper temperatures
- Refrigerated or frozen promptly
Some foods are more likely to cause food poisoning. For example, undercooked meats, poultry, shellfish, soft cheeses, deli meats, raw eggs, vegetables, and fruits have a higher risk of contamination and can make you sick.
While there are more than 250 types of food poisoning, the U.S. Department of Health and Human Services explains that the most common bacterial causes may include:
- Salmonella (the most common cause of bacterial food poisoning in the U.S.)
- E. coli
- Listeria
- Staphylococcus
- Campylobacter
- Shigella
Viral infections like norovirus (also the virus most commonly associated with stomach flu) and hepatitis A can also cause food poisoning. Whenever you eat something toxic—whether it’s infected by bacteria, viruses, or other toxins—your immune system kicks in to flush it out fast. As your body works to clear the bug, you might have uncomfortable symptoms like:
- Diarrhea
- Nausea and vomiting
- Stomach pain and cramping
- Fever
- Headache
- Weakness
Causes and symptoms of the stomach bug
“A stomach bug [also known as gastroenteritis] is a general term that usually describes an infection of the stomach,” Dr. Ivanina says. While any bad bugs (e.g., bacteria and parasites) can cause a stomach infection, it’s a good bet that a virus is to blame.
Viral gastroenteritis infects as many as 21 million people in the U.S. every year, per the NIDDK. However, norovirus accounts for approximately half of those cases. Like other stomach viruses, norovirus lives in the poop and vomit of infected people. Tiny traces of it can stick around on hands or surfaces, transferring to food, water, or anything you touch. If you eat contaminated food or touch your mouth after contact, you could become exposed to the virus.
It’s worth noting that viral gastroenteritis is also dubbed as the stomach flu, but it actually has nothing to do with “the flu” (aka influenza), which affects your respiratory system. Different viruses cause each infection, and they target different parts of the body. The nickname likely stuck because both illnesses are common and hit during “flu season,” so people often use “flu” to describe they’re feeling sick.
According to the NIDDK, the most common symptoms of the stomach flu include:
- Diarrhea
- Nausea and vomiting
- Abdominal pain and cramping
- Fever, in some cases
However, if your stomach infection is hitting you hard, your immune system might mount an even stronger response. When this happens, you might have symptoms outside of your digestive system. According to the Mayo Clinic, these may include:
- Fever
- Chills
- Nausea or vomiting
- Fatigue
- Body aches
- Headaches
What’s the difference between the two infections?
Sometimes it can be tough to tell whether you’re fighting off food poisoning or a stomach bug (especially since norovirus can cause both!). “In fact, norovirus is the leading cause of vomiting, diarrhea, and foodborne illness in the United States,” Dr. Ivanina says.
Though it’s not always cut and dry, here are a few ways to try to distinguish whether you picked up germs from bad food or a sick person.
1. Food poisoning symptoms appear faster
In general, “food poisoning comes on quickly, usually a few hours after you’ve eaten bad food,” Dr. Ivanina says. On the other hand, “a stomach bug usually has a longer incubation period,” typically between 24 to 48 hours before symptoms start, she adds.
2. The stomach flu lasts longer
“Food poisoning usually lasts about 24 hours,” Dr. Ivanina says. But it can vary, especially if your illness is caused by a stubborn parasite or if you live with a weakened immune system. However, the stomach flu clears up after a few days but may linger up to a week or two in severe cases or if you’re immunocompromised.
3. Stomach bugs are very contagious
Stomach bugs like norovirus are extremely contagious. To avoid spreading them, limit your contact with others, wash your hands often, disinfect shared surfaces (especially in the bathroom), and don’t prepare food for your loved ones until you’ve been symptom-free for 48 hours, Dr. Invanina says.
On the other hand, food poisoning happens when you eat contaminated foods, not from contact with another person. Meaning, it’s usually not contagious. However, in some situations, you can potentially spread the bacteria and viruses that cause food poisoning to other people. We know, it’s a bit confusing. Take this example to illustrate: Say you get sick from listeria by eating a contaminated hotdog and you develop food poisoning. But, if your partner picks up your listeria germs (through contact with your puke or poop), they can get ill too.
How to treat both infections
In most cases, food poisoning and stomach bugs will run their course within a few days without treatment. In the meantime, here are some at-home treatment options you can try to help your body heal whether you ate spoiled food or caught a stomach virus from another person.
- Rest: Sleep gives your body the energy it needs to fight the infection.
- Drink fluids: Consume electrolyte drinks, water, soup, or bone broth to replenish lost fluids.
- Eat bland foods: After severe symptoms have subsided and your body feels okay enough to consume food, start with bland foods. This will usually include low-fiber foods like white rice, oatmeal, bananas, and chicken. These foods are easy to digest and help you regain some energy.
- Avoid trigger foods: Foods high in sugar, fat, dairy, and gluten can make symptoms worse. Additionally, it’s a good idea to avoid alcohol and processed foods until symptoms completely go away and you have recovered.
While these home remedies are enough for most people, some groups may require more treatment. This includes young children, pregnant people, older adults, and folks living with chronic illnesses. If you or a loved one is having severe symptoms that aren’t improving with home remedies, it’s important to reach out to a healthcare provider for medical options like intravenous fluids or medications that can help manage symptoms.
How to prevent food poisoning and stomach bugs
You can lower your odds of getting (or spreading) food poisoning or a stomach bug by practicing good hygiene. Follow these tips from Dr. Ivanina:
- Always wash your hands after doing things like changing diapers, going to the bathroom, and blowing your nose, and before preparing food
- Stay home from school or work when you are sick, and isolate yourself when you are symptomatic to avoid spreading infection to others
- Do not drink unpasteurized or raw milk or foods made with it
- Wash fruits and vegetables before eating them
- Keep the refrigerator colder than 40 degrees Fahrenheit and the freezer below 0 degrees Fahrenheit
- Cook meat and seafood until well done, and eggs until yolk is firm
- Wash hands, knives, and cutting boards after they touch raw food
When to see a healthcare provider
Though stomach cramps, puking, and pooping can be unpleasant, these symptoms are actually a sign that your immune system is fighting like it should. In most cases, your body will typically clear food poisoning or a stomach infection within a few days. However, if your symptoms don’t get any better (or worsen) after 24 to 48 hours, it’s a good idea to check in with your healthcare provider. According to Dr. Ivanina, seek medical attention if you have:
- Frequent diarrhea or vomiting that leave you dehydrated (FYI, signs of dehydration include fatigue, thirst, dry mouth/tongue, muscle cramps, dizziness, confusion, very yellow urine, or less frequent urination)
- Blood in your vomit or stool
- A fever higher than 101.3 degrees Fahrenheit that persists
- Severe abdominal pain
In some cases, your healthcare provider may test your stool to see what bacteria or virus is causing your symptoms, Dr. Ivanina says. Knowing the exact cause can help you and your provider understand which treatments you need to get yourself back on your feet and live well.
