Quick answer
What is antibiotics used for?
Antibiotics are medicines that treat infections caused by bacteria. They do not work against viruses, so they will not help colds, flu or most coughs and sore throats. Using them only when truly needed, and finishing the course as prescribed, helps keep them working.
What are antibiotics?
Antibiotics are medicines used to treat or prevent some types of infection caused by bacteria. They work by killing bacteria or stopping them from multiplying. They are powerful and important medicines — but only for the right kind of infection.
What antibiotics do and don’t treat
Antibiotics only work against bacterial infections, such as some urine, chest, skin and throat infections. They do not work against viruses, which cause most coughs, colds, flu and sore throats. Taking antibiotics for a viral illness will not help you recover and can do harm.
Using antibiotics safely
If you are prescribed antibiotics:
- take them exactly as directed, at the right times
- follow your prescriber’s advice on how long to take them
- tell your GP or pharmacist about any allergies or other medicines you take
- do not share antibiotics or save them for another time
Always read the patient information leaflet, which explains how to take your specific antibiotic and what side effects to look out for.
Side effects and allergies
Like all medicines, antibiotics can cause side effects — commonly mild things such as feeling sick or having loose stools. Some people are allergic to certain antibiotics. A serious allergic reaction (with swelling, difficulty breathing or a widespread rash) is a medical emergency.
Why “only when needed” matters
Using antibiotics when they are not needed makes them less effective over time, because bacteria become resistant. This is a major global health concern. By only using antibiotics when a doctor judges them necessary, we help keep them working for everyone.
Common questions
- Why won't my doctor give me antibiotics for a cold?
- Colds, flu and most coughs and sore throats are caused by viruses, which antibiotics cannot treat. Taking antibiotics when they will not help can cause side effects and contributes to antibiotic resistance, so doctors prescribe them only when a bacterial infection is likely.
- What is antibiotic resistance?
- Antibiotic resistance is when bacteria change so that antibiotics no longer kill them. The more antibiotics are used unnecessarily, the faster this happens — which is why it is important to use them only when genuinely needed.
- Should I finish the whole course?
- Take antibiotics exactly as prescribed. Follow your prescriber's instructions on how long to take them, and do not stop early or save some for later unless told to. If you are unsure, ask your pharmacist.
- Can I drink alcohol with antibiotics?
- With most antibiotics, moderate alcohol does not cause a serious problem, but with a few types it must be avoided completely. Check the patient information leaflet or ask your pharmacist about your specific antibiotic.