What are antibiotics?
Antibiotics are medicines that fight bacterial infections in people and animals. They work by killing the bacteria or by making it hard for the bacteria to grow and multiply.
Antibiotics can be taken in different ways:
- Orally (by mouth). This could be pills, capsules, or liquids.
- Topically. This might be a cream, spray, or ointment that you put on your skin. It could also be eye ointment, eye drops, or ear drops.
- Through an injection or intravenously (IV). This is usually for more serious infections.
What do antibiotics treat?
You may not need to take antibiotics for some bacterial infections. For example, you might not need them for many sinus infections or some ear infections. Taking antibiotics when they're not needed won't help you, and they can have side effects. Your health care provider can decide the best treatment for you when you're sick. Don't ask your provider to prescribe an antibiotic for you.
Do antibiotics treat viral infections?
Antibiotics do not work on viral infections. For example, you shouldn't take antibiotics for:
- Colds and runny noses, even if the mucus is thick, yellow, or green
- Most sore throats (except strep throat)
- Most cases of bronchitis
What are the side effects of antibiotics?
The side effects of antibiotics range from minor to very severe. Some of the common side effects include:
More serious side effects can include:
- C. diff infections, which cause diarrhea that can lead to severe colon damage and sometimes even death
- Severe and life-threatening allergic reactions
- Antibiotic resistance infections
Call your health care provider if you develop any side effects while taking your antibiotic.
Why is it important to take antibiotics only when they're needed?
You should only take antibiotics when they are needed because they can cause side effects and can contribute to antibiotic resistance. Antibiotic resistance happens when the bacteria change and become able to resist the effects of an antibiotic. This means that the bacteria continue to grow.
How do I use antibiotics correctly?
When you take antibiotics, it is important that you take them responsibly:
- Always follow the directions carefully. Finish your medicine even if you feel better. If you stop taking them too soon, some bacteria may survive and re-infect you.
- Don't save your antibiotics for later.
- Don't share your antibiotic with others.
- Don't take antibiotics prescribed for someone else. This may delay the best treatment for you, make you even sicker, or cause side effects.
Centers for Disease Control and Prevention
- Antibiotic Do's and Don'ts (Centers for Disease Control and Prevention)
- Antibiotic Use Questions and Answers: What Everyone Should Know (Centers for Disease Control and Prevention) Also in Spanish
- Antibiotics: When They Can and Can't Help (American Academy of Family Physicians) Also in Spanish
- Antibacterial Agents (Alliance for the Prudent Use of Antibiotics)
- Antibiotic Resistance: MedlinePlus Health Topic (National Library of Medicine) Also in Spanish
- Antibiotic-Associated Diarrhea (Mayo Foundation for Medical Education and Research) Also in Spanish
- Chest Cold (Acute Bronchitis) (Centers for Disease Control and Prevention) Also in Spanish
- Common Cold (Centers for Disease Control and Prevention)
- Ear Infection (Centers for Disease Control and Prevention)
- Flu (Influenza) (Centers for Disease Control and Prevention)
- Penicillin Allergy (Mayo Foundation for Medical Education and Research) Also in Spanish
- Sinus Infection (Sinusitis) (Centers for Disease Control and Prevention) Also in Spanish
- Skin Infections (Centers for Disease Control and Prevention)
- Sore Throat (Centers for Disease Control and Prevention)
- Urinary Tract Infection (Centers for Disease Control and Prevention) Also in Spanish
- Be an Antibiotics Whiz: Test Your Knowledge about Antibiotics (Centers for Disease Control and Prevention)
- ClinicalTrials.gov: Anti-Bacterial Agents (National Institutes of Health)
Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)
- Article: Let's Talk About Antibiotics: a randomised trial of two interventions to...
- Article: Antibiotic review kit for hospitals (ARK-Hospital): a stepped-wedge cluster-randomised controlled trial.
- Article: Feedback of Antibiotic Prescribing in Primary Care (FAPPC) trial: results of...
- Antibiotics -- see more articles
- Antibiotics and Resistance: Glossary (Alliance for the Prudent Use of Antibiotics)
Find an Expert
- Centers for Disease Control and Prevention Also in Spanish
- Food and Drug Administration
- National Institute of Allergy and Infectious Diseases
- Danger of Antibiotic Overuse (For Parents) (Nemours Foundation) Also in Spanish