Influenza (flu) is an infection, caused by a virus, that makes you feel very sick, often with fever, headache, body aches, and coughing.
People often use the term "flu" to describe a cold or a stomach virus. But influenza isn't a stomach problem, and it usually feels much worse than a cold.
|Primary Medical Reviewer||E. Gregory Thompson, MD - Internal Medicine|
|Specialist Medical Reviewer||Christine Hahn, MD - Epidemiology|
|Last Revised||October 9, 2012|
WebMD Medical Reference from Healthwise