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Cold, Flu, & Cough Health Center

Select An Article

Is It a Stomach Flu or Influenza?

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What Causes It? continued...

While they’re not as common, parasites like giardia and cryptosporidium can cause severe diarrhea and dehydration. They’re often found in parts of the world where the water isn’t clean. Travelers should drink bottled water to avoid them.

Some foods may irritate your stomach and also cause gastroenteritis. The way someone who can’t digest dairy (or is lactose intolerant) reacts to dairy products is a good example. Severe reactions to seafood are another example.

Who's Most Likely to Get It?

Those high on the list are pregnant women, infants, people who aren’t eating well, people whose immune systems are weakened, and older adults.

How severe your case is depends on how well your body can resist the infection.

When Should You Call the Doctor?

If you have symptoms of stomach flu and are weak and dizzy, you may be dehydrated. Call your doctor if you have these symptoms.

  • Blood in your vomit or poop
  • Dehydration -- you can’t pee, or there’s very little when you do go, you’re very thirsty, can’t make tears, and your mouth is always dry
  • Fever of 100.4 degrees F or higher in an infant or 102.2 degrees F or higher in an older child or adult
  • Swollen tummy or pain in the right lower part of the belly
  • Vomiting that lasts more than 48 hours

If you can’t keep fluids down and you’re losing them from fever, vomiting, and diarrhea, get emergency medical help. Tell friends and family that if you pass out, someone should call 911.

WebMD Medical Reference

Reviewed by Melinda Ratini, DO, MS on March 28, 2015
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