Fever: Common Questions
A raised body temperature, usually part of the immune response to infection.
Last revised
Fever: the questions people actually ask, answered from published guidance.
Key takeaways
- Commonly defined as: 38C or above
- In babies under 3 months: 38C or above needs urgent assessment
- Most useful single change: Keep fluids up; this matters more than lowering the temperature.
- Commonest mistake: Alternating paracetamol and ibuprofen routinely without advice.
- See a doctor if any of the signs under "When to get help" below apply to you.
What is Fever?
A raised body temperature, usually part of the immune response to infection.
Why does it matter?
It is a sign rather than a disease, and the number matters far less than how the person looks and behaves.
Commonly defined as for Fever?
38C or above.
In babies under 3 months for Fever?
38C or above needs urgent assessment.
Paracetamol and ibuprofen for Fever?
For discomfort, not to normalise the number.
Do not give aspirin for Fever?
To anyone under 16.
What is the single most useful thing to do?
Keep fluids up; this matters more than lowering the temperature.
What is the most common mistake?
Alternating paracetamol and ibuprofen routinely without advice.
When should I see a doctor?
Call 999 for a rash that does not fade under pressure, a stiff neck with light sensitivity, a seizure, difficulty breathing, or a child who is floppy, will not wake or is unusually drowsy. Any fever of 38C or above in a baby under three months needs urgent assessment. Seek urgent advice for fever in anyone immunosuppressed or having chemotherapy.
Where to go next
- What People Get Wrong About Fever
- Starting Out With Fever
- Fever — the reference entry
- Vitamin C: What the Evidence Actually Says
- Zinc: What the Evidence Actually Says
When to get help
Call 999 for a rash that does not fade under pressure, a stiff neck with light sensitivity, a seizure, difficulty breathing, or a child who is floppy, will not wake or is unusually drowsy. Any fever of 38C or above in a baby under three months needs urgent assessment. Seek urgent advice for fever in anyone immunosuppressed or having chemotherapy.
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.
