A few key differences can clue you in.

By Stephanie Booth
November 27, 2018

You're racked by nausea, your stomach is doing flip-flops, and your toilet has become your new best friend. As you make yet another dash to the bathroom and anxiously ponder what the hell is going on, two possibilities pop into your head. You've come down with the stomach flu, or you've contracted food poisoning.

But how do you tell the difference? That's where things get tricky.

“The stomach flu and food-borne illness are easy to confuse because the symptoms are almost identical,” Niket Sonpal, MD, assistant clinical professor at Touro College of Osteopathic Medicine in New York City and St. George's University School of Medicine specializing in gastroenterology and internal medicine, tells Health. Those symptoms, as you well know, include severe nausea, stomach cramps, diarrhea, and vomiting.

RELATED: How Do You Get the Stomach Flu?

A quick word about each illness. What's colloquially called stomach flu isn't influenza at all but usually a norovirus, a family of highly contagious viruses that wreak ruthless havoc on your gastrointestinal tract. Norovirus is contracted by touching a surface where the bug is lurking and then touching your mouth, via close contact with someone already infected, or by eating food contaminated by someone carrying the virus. Under a microscope, norovirus looks fittingly like the Death Star.

Food poisoning, on the other hand, is an umbrella term for any of the more than 250 food-borne illnesses researchers have so far identified. They can be caused by bacteria, parasites, and viruses; norovirus transmitted through food could be considered a food-borne illness. Others include salmonella, which you can get from foods like undercooked poultry or meat, and listeria, which is linked to soft cheeses, raw bean sprouts, and melons, among others.

While they are distinct illnesses that share many characteristics, stomach flu and food poisoning do have a few differences when it comes to their symptoms. These questions can help you decode which one you likely are dealing with.

Do you have other symptoms besides GI issues?

Again, ongoing diarrhea attacks and a vomit-thon are the main signs. But stomach-flu sufferers can also have "additional extra-intestinal symptoms, or things that happen outside of your GI tract,” says Dr. Sonpal. “These can be signs of dehydration like headache, lightheadedness and dry mouth.”

People with food poisoning can also experience non-stomach related signs. Depending on the germ you’ve regrettably swallowed, you could also have flu-like symptoms (like a fever), increased gas, and in rare cases much scarier symptoms such as slurred speech, drooping eyelids, or a loss of balance, according to the Centers for Disease Control (CDC). Weakness, body aches, or even a rash are also possible signs, says Janette Nesheiwat, MD, a board-certified family and ER doctor in New York City.

RELATED: 13 Things You Should Know About Stomach Flu

How long did it take for the symptoms to show up?

In general, if you've picked up norovirus, the first signs of the illness will appear within 12-48 hours, according to the CDC.

For food poisoning, it depends. If your symptoms are caused by a microbe, you might not feel bad until 3-4 days after consuming it in your food. But if the awfulness is caused by a reaction to a toxin released by the microbe, the discomfort comes on much faster. “Eat something in the morning, and you can have symptoms that afternoon,” Van Pham, DO, primary-care physician at MemorialCare Medical Group in Long Beach, California, tells Health.

What to do when you’re sick with either

When it comes to treating the stomach flu, sadly, there’s no magic pill that will make you stop puking your guts out. Instead, you’ve got to wait until your body fully flushes norovirus from your system. The good news? Norovirus “is very self-limited and lasts 3 to 4 days for most people,” says Dr. Pham.

If you have food poisoning, you’ll also have to wait it out anywhere from a few hours to several days, according to the CDC, though this depends on the actual microbe causing your distress. Most people recover with no issues.

RELATED: 12 Germs That Cause Food Poisoning

While you’re riding it out, it’s crucial to keep drinking fluids so you don’t get dehydrated. If your diarrhea is severe, the CDC recommends sipping Ceralyte, Oralyte, or Pedialyte to correctly replace your electrolytes. Skip the sports drinks; they don’t contain enough sodium or potassium to do much good and are high in sugar, which may only make your diarrhea worse.

If things don't clear up or at any point you experience a high fever, bloody diarrhea, diarrhea lasting more than three days, or you can’t keep any fluids down, call your doctor. In the meantime, get as much rest as you can and keep telling yourself: whether you’ve contracted the stomach flu or food poisoning, this too shall pass.

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