Not feeling well? Ready to ask your doctor for medicine to help you feel better? If you have a cold, the flu or a virus, an antibiotic will not work as well as rest, fluids and time. While antibiotics are useful medicines that combat life-threatening infections caused by bacteria, they are not effective against viral infections. In fact, the widespread use of antibiotics promotes the development of drug-resistant bacteria. Read these tips to help you prevent antibiotic resistance.