For more on the flu, visit: www.cdc.gov/flu

What's "stomach flu"?

Have you heard people talk about "stomach flu"? Gastroenteritis, which some people call "stomach flu", is not influenza at all. It's caused by bacteria or other viruses — not the influenza virus — and the primary symptoms of stomach flu are vomiting and diarrhea.

With seasonal flu you may, in rare instances, experience vomiting as well, but the major difference between so-called "stomach flu" and seasonal flu is that severe respiratory problems can accompany seasonal flu. These may include difficulty breathing and pneumonia. Be sure to check with your doctor if you have any of these symptoms.