What should i do when i have a flu?

Depends on cause...: A cold caused by cold viruses is usually left alone, or one can try over-the-counter cold medications. The flu caused by influenza viruses is treated by antiviral drugs and cold medications. A sore throat is tested to see if it is strep throat. If strep, antibiotics are needed (if not strep, the sore throat may be due to "cold viruses" or another cause). This all may mean seeing a doctor.