Influenza is primarily a disease caused by an infection of the upper respiratory tract with the influenza virus. It is a contagious disease that can spread among people, leading to an outbreak. Although influenza is a frightening illness, it is a viral infection characterized by being self-limiting, meaning that whether or not medication is used, the patient's condition can improve on its own. Typically, the course of influenza can improve on its own within about 7 to 10 days. At this time, it is sufficient to use medications that reduce fever, relieve pain, or treat nasal congestion and coughing, since patients generally recover on their own after about 7 days, and medication is only needed to alleviate symptoms. (Please use medication under the guidance of a doctor.)