Stomach flu is an infection that is caused by a virus. Medically referred to as viral gastroenteritis, it afflicts both the stomach and the small intestine. Stomach flu is not at all related to influenza and is not caused by one particular virus. It can be caused by many different viruses and stomach flu is simply used as a catchall phrase.

The most common symptoms of the stomach flu include nausea, vomiting, and diarrhea. Often, stomach cramps and chills are present. Mild fever, fatigue, appetite loss, and muscle aches are also common symptoms of stomach viruses. Symptoms may develop gradually over many hours or the onset may be quite sudden; generally, symptoms last from one to three days. The stomach flu is diagnosed based on a healthcare provider's review of a patient's symptoms; lab tests may be given to make certain a more serious illness is not responsible for the symptoms, as well as to discover complications.

Among the viruses that cause stomach flu are rotaviruses and adenoviruses. The Norwalk virus is a frequent culprit as well. An individual can contract the stomach flu by swallowing a virus that causes it. For example, an individual can contract the stomach flu from kissing and sharing food or eating utensils with an infected person. A person can even contract it by shaking hands with an infected individual and then eating without washing his hands properly.

Viruses that cause the stomach flu are contained in the bodily fluids of infected individuals. A stomach flu virus may be present even before symptoms are present. Once an uninfected person encounters the bodily fluids of an infected individual and swallows the virus, trouble begins. The virus travels down to the stomach and on to the intestines, causing inflammation in both places. This temporarily impairs the function of these organs and symptoms become obvious and unpleasant.

Treatment for the stomach flu includes resting the digestive system. This means avoiding solid foods for a period of time and staying hydrated with clear liquids. Once vomiting is under control, soft, bland foods may be consumed. If vomiting is frequent, sticking to small sips of water is wise. Though it is important to stay hydrated while dealing with the stomach flu, too much liquid at once can cause vomiting to increase.

Water is generally a good choice for staying hydrated during the stomach flu. However, an electrolyte-replacement drink may be a better idea if vomiting has been occurring for a longer period of time. Weak tea may also be consumed and some suggest drinking flat, decaffeinated soda as well. It is best to avoid milk, citrus juice, caffeine, and carbonated beverages while you are sick with the stomach flu.