Catching a flu can make it harder to manage daily life, so you should do everything you can avoid cold or flu. When you are sick with a flu, your body sends out hormones to fight the infection. Having flu may curb your appetite, but it is important to eat something anyway. If you have a fever, vomiting, or diarrhea, you will have to be careful not to allow your body to become dehydrated. Try to average about 1 cup of fluid every hour. If you are diabetic then choose water or sugar-free liquids. There is no medicine that will prevent or cure the common cold or flu, but there are medicines that can relieve some of the symptoms. These tips may help in flu: Take vitamin C espacially from natural source like lemon juice, orange juice, pomegranate juice, etc. Drink Black tea/Green tea/herbal tea without sugar and milk. Brsh and floss your teeth twice a day. If you smoke, quit. Take care of your general health.