To fight the spread of antibiotic-resistant infections, everyone needs to be smart about using antibiotics. Keep these tips in mind: 1. Antibiotics are effective only for bacterial infections. They don't work for viral illnesses, such as the common cold. 2. If your doctor prescribes antibiotics, take them exactly as directed. Don't stop treatment early, even if you start feeling better. 3. Never take antibiotics that were prescribed for someone else.