10 Misconceptions About the Flu

'Stomach Flu' Is a Form of Influenza
Dr. Robert Hernandez (left) speaks with Connie Adams as she lies in a bed suffering the effects of dehydration resulting from a stomach virus in Louisiana. Mario Villafuerte/Getty Images

You've probably heard people over the years complain that they're feeling awful and can't keep down solid food because they've come down with something they call the "stomach flu." Unless you have a medical degree, the term makes it easy to confuse that sort of sickness with influenza, but it's really a misnomer. Influenza is a respiratory illness that afflicts the lungs and breathing passages, not the gastrointestinal system. And while vomiting, diarrhea and being sick to your stomach sometimes can be caused by influenza -- usually in kids -- those aren't the main symptoms of the flu, and they're often caused by something else [source: CDC].

So what is the "stomach flu," if it isn't actually influenza? Gastrointestinal discomfort can be caused by a variety of other viruses, bacterial infections and even parasites [source: CDC]. Most often, the stomach flu's unfortunate victims are suffering from some sort of food-borne illness, according to Dr. Tony Brayer, chief medical officer for Sutter Health West Bay Region in California.

But that's scant comfort. Food poisoning, to use the old-fashioned term, is probably just as common as the flu, and it can be just as dangerous. About 48 million Americans are sickened by tainted food each year, with 128,000 of them requiring hospitalization. About 3,000 people die annually from food-borne illnesses. And you can get them at home from food in your refrigerator, just as easily as you can at a greasy-spoon lunch counter or a salad bar without a sneeze guard. Undercooked poultry, meat, unwashed produce and unpasteurized raw milk are common sources [source: Brayer].