But medical information is always changing, and some information given here may be out of date. For regularly updated information on a variety of health topics, please visit familydoctor.org , the AAFP patient education Web site. Antibiotics are strong medicines that can stop some infections and save lives. When they aren't used the right way, antibiotics can cause more harm than good. You can protect yourself and your family by knowing when you should use antibiotics and when you should avoid them.
Antibiotics only work against infections caused by bacteria .
They don't work at all against infections caused by viruses. Viruses cause the flu, colds, and most coughs and sore throats. Usually antibiotics kill bacteria or stop them from growing, but some bacteria have grown so strong that antibiotics don't work against them. Resistant bacteria develop when antibiotics are used too often or are not used correctly. Resistant bacteria sometimes can be treated with more powerful medicines.