Is It Food Poisoning or the Stomach Flu?

You're dealing with major GI problems — think: nausea, cramps, vomiting and diarrhea — that seemed to come on out of nowhere. Do you have a stomach bug...or was it something you ate?

Both the stomach flu and food poisoning can leave you feeling similarly lousy. But they're two different illnesses with different causes.

Food poisoning happens when you eat food contaminated with a bacteria (think: salmonella or E. coli) or another pathogen. The stomach flu, or what doctors usually call viral gastroenteritis, is a viral infection of the stomach and intestines typically passed from person to person. (And despite the name, it's ‌not‌ actually related to influenza.)

Here's how you can tell the difference when you're under the weather, plus what you can do to feel better and how to steer clear of getting sick next time.

Food poisoning and the stomach flu can cause similar symptoms. But they're not identical, and you might feel the effects of the former sooner than the latter.

Per the Cleveland Clinic, common signs of food poisoning include:

• Diarrhea
  
• Nausea
  
• Vomiting
  
• Stomach pain or cramping
  
• Fever
  
• Headache
  
• Weakness
  

Food poisoning symptoms can strike fast after eating the offending food.

"It usually begins six to 24 hours after exposure to bacteria or...a toxin," says Robert Glatter, MD, an emergency care physician at Lenox Hill Hospital in New York City. "In some cases, symptoms can begin as soon as two to four hours after exposure."

The Cleveland Clinic notes that stomach flu is usually marked by:

• Diarrhea
  
• Nausea
  
• Vomiting
  
• Loss of appetite
  
• Stomach pain and cramping
  

In cases of severe infection, you might have body-wide symptoms such as fever, chills, fatigue, body aches, headache and swollen lymph nodes.

Stomach flu symptoms can be a bit slower to come on. Most people will start to feel sick within 24 to 48 hours after being exposed to the virus, Dr. Glatter notes.

Food poisoning and the stomach flu can often feel similar, but their underlying causes set them apart.

Food poisoning happens from eating or drinking something that's contaminated, usually by bacteria or a toxin.

That can happen when a food isn't washed or stored properly, is undercooked, isn't kept at the proper temperature or isn't handled in a sanitary way (like not washing your hands or your cutting board).

Any food can become contaminated and cause food poisoning. But according to the Centers for Disease Control and Prevention (CDC), the most likely culprits include:

• Raw and undercooked meat, poultry, seafood or eggs
  
• Raw or unpasteurized dairy
  
• Raw fruits or vegetables, especially leafy greens and sprouts
  
• Raw grains, including flour

Gastroenteritis, on the other hand, is caused by a viral infection. Norovirus is the most common offender, Dr. Glatter says, with rotavirus being a close second.

And even though people sometimes call it the stomach flu, it's not related to the virus that causes influenza. The ‌real‌ flu is a respiratory infection, not a stomach bug, notes the National Library of Medicine.

The viruses that cause gastroenteritis are highly contagious. The germs can hop from one person to another via close contact or by sharing things like food, utensils, water, towels or bedsheets. You can also get sick by touching your mouth, lips or nose after touching a contaminated surface, like a doorknob or remote.

And here's something gross but true: Germs like norovirus can easily become aerosolized, meaning they're transmitted via microscopic droplets from a flushing toilet or vomit, Dr. Glatter says.

So how long will you be in gastrointestinal misery for? Most healthy people will clear a food poisoning infection within 12 to 48 hours, though it could take longer if you have a condition that weakens your immune system, says the Cleveland Clinic. The stomach flu typically causes its most intense symptoms for about the same amount of time.

You might not necessarily feel back to normal once the diarrhea and vomiting have passed, though. Per the Mayo Clinic, some people will have lingering symptoms like nausea, cramping, gas and bloating for up to 14 days.

If symptoms last beyond that, it's possible you have a case of post-infectious irritable bowel syndrome, which warrants a trip to your doctor.

For most people, a case of food poisoning or the stomach flu simply needs to run its course. In the meantime, the following can help ease symptoms and support your recovery, per Dr. Glatter:

Take steps to try to avoid becoming dehydrated from vomiting or diarrhea, Dr. Glatter recommends. Take frequent, small sips of water or other fluids like clear broths or sports drinks.

If you become dehydrated, you may need to go to the hospital to receive IV fluids.

Give your stomach a break by avoiding eating when your symptoms are at their worst.

Ease back into food as your appetite starts to return by sticking with a bland diet. Think: crackers, toast, noodles, bananas or rice, the Mayo Clinic recommends.

Try to take it easy and allow yourself plenty of time to rest and recover.

Some cases of food poisoning or gastroenteritis might call for antiparasitic or antibiotic medications. Your doctor can help you decide if treatment is right for you.

The No. 1 way to reduce your risk for food poisoning or the stomach flu? "Wash your hands," Dr. Glatter recommends.

Frequent sudsing will reduce the chance that germs you pick up on your hands end up making you sick or contaminating your food.

Lather up in these cases:

• After using the bathroom
• Before and after preparing food
• Before you eat
• Before and after you come in contact with someone who is sick
• Before and after diaper changes
• Before and after treating a cut or wound
• After coughing, sneezing or blowing your nose
• After touching an animal, animal feed or animal waste
• After touching garbage
• After touching shared surfaces, such as in the gym or on a train

Smart food prep habits can help minimize your chance for food poisoning. Per the CDC:

• Wash surfaces like cutting boards, utensils and countertops before cooking.
• Keep raw meat, poultry and seafood away from anything that's ready to eat.
• Cook foods to a safe internal temperature.
• Refrigerate leftovers within two hours of cooking.

Avoid close contact with someone who has the stomach flu.

"Do not share eating utensils, drinking glasses or cups," Dr. Glatter warns. "Additionally, make sure you don't share towels, and change sheets and pillowcases frequently."

Keep the toilet seat down before flushing, too, to prevent aerosolized droplets from landing on nearby bathroom surfaces.

Food poisoning and the stomach flu will usually clear up on their own within a few days. You should seek medical attention for severe symptoms, though, which could be a sign of dehydration or a serious infection.

"Seek care in the emergency department if you develop dizziness, weakness, a progressively higher fever, bloody diarrhea or worsening headache," Dr. Glatter says.