First thing to do when a cold or flu hits...by Dr Mercola

Since colds are viral in nature, antibiotics are completely useless and should be avoided, unless your physician diagnoses a serious secondary bacterial infection. Using antibiotics when no bacterial pathogen is present simply contributes to the problem of antibiotic-resistant disease. The key to preventing colds and recovering from them quickly is to maintain a strong immune system, which includes: optimizing your diet, avoiding sugar, optimizing your vitamin D level, getting enough sleep and exercise, managing your stress, and practicing good hand washing technique.