What Causes Stomach Flu?

A girl vomiting. Image Source/Getty Images

The "stomach flu", or gastroenteritis, can be caused by many things, but none of them are actually the flu. While the flu is a respiratory illness caused by a virus called influenza, the "stomach flu" is an infection in the gastrointestinal lining. It can be caused by a bacteria, a virus or even a parasite.

Some common causes of stomach flu are:

  • Rotavirus (virus)
  • Adenovirus (virus)
  • Giardia (parasite)

The stomach flu is typically caused by one of the germs listed above and usually resolves on its own after a few days.

Symptoms may differ slightly depending on which virus, bacteria, or parasite is causing the stomach flu, but your doctor can usually figure out if treatment is needed based on the symptoms you are experiencing.


"Viral Gastroenteritis." Division of Viral Diseases 25 Feb 11. National Center for Immunization and Respiratory Diseases. US Centers for Disease Control and Prevention. 09 Mar 11.

Continue Reading