Antibiotics can cure bacterial infections but are ineffective against viral infections. The common cold and the flu are viral infections, so avoid seeking antibiotics if you suffer from either of these illnesses. Overuse of antibiotics when they are not needed is a significant factor in some bacteria becoming resistant to the antibiotic, potentially reducing that antibiotic’s future effectiveness. It’s not always obvious whether an infection is viral or bacterial. Consult your doctor or pharmacist to determine what is the right treatment for you.