Antibiotics
Medicines that kill or inhibit bacteria, and do nothing whatever to viruses.
Last revised
Key takeaways
- What they target: bacterial cell walls, ribosomes and DNA replication
- Why they fail on viruses: viruses have none of those structures
- Most useful single change: Ask what symptoms should prompt you to come back, and by when.
- Commonest mistake: Pressing for antibiotics because mucus has turned green.
- See a doctor if any of the signs under "When to get help" below apply to you.
Why it matters
Unnecessary courses give you the side effects without the benefit and contribute to resistance that is already attributed to over a million deaths a year.
The numbers, in one place
| Measure | Figure |
|---|---|
| What they target | bacterial cell walls, ribosomes and DNA replication |
| Why they fail on viruses | viruses have none of those structures |
| Cause of green mucus | an enzyme in white blood cells, not bacteria |
| Deaths attributed to resistance globally | over a million a year |
| Useful middle ground | a delayed or back-up prescription |
What helps
- Ask what symptoms should prompt you to come back, and by when
- Finish the course exactly as prescribed when they are indicated
- Return unused antibiotics to a pharmacy
- Accept a delayed prescription where offered; it is evidence-based
What to avoid
- Pressing for antibiotics because mucus has turned green
- Taking leftovers, or someone else's
- Assuming a longer illness means a bacterial one
Where to go next
- Your Questions About Antibiotics, Answered
- Antibiotics: The Quick Reference
- What the Guidance Really Says About Hand Hygiene
- The Evidence on Fever, Without the Hype
When to get help
Contact a GP or NHS 111 for a cough lasting more than three weeks, fever persisting beyond five days, symptoms that improve then suddenly worsen, or difficulty swallowing with a sore throat. Call 999 for difficulty breathing, confusion, or a rash that does not fade when pressed with a glass.
Where this comes from
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarised or generalised beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to a GP, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 999.