Fever in children: what counts, what to do, when to give medicine
Fever is a symptom, not an illness, and on its own is rarely dangerous. Treat the child, not the thermometer: how they look, whether they drink, and the red flags matter more than the number.
Last updated: 24 September 2026
What counts as a fever
| Temperature | Name | Usual action |
|---|---|---|
| 36.0–37.0 °C | normal | nothing |
| 37.1–37.9 °C | raised | watch, offer drinks, no medicine |
| 38.0–38.9 °C | fever | medicine if the child is uncomfortable |
| 39.0–39.9 °C | high fever | medicine; if it does not drop or lasts over 3 days — doctor |
| ≥ 40.0 °C | very high | medicine and contact a doctor |
When to give a fever medicine
NICE and the AAP agree: give medicine when the child is distressed — irritable, in pain, not drinking, not sleeping — not to chase a number. A playful child at 38.5 °C does not need it; a crying child with ear pain at 38.2 °C does.
Besides medicine
- Fluids matter most: small amounts, often.
- Light clothing, room around 20 °C. No cold baths or alcohol rubs — they cause shivering and stress and do not lower the temperature for long.
- Do not wake a sleeping child to measure.
How long is normal
A common viral infection gives 2–3 days of fever. More than 3 days, or fever returning after a fever-free day, deserves a visit.
Febrile seizures
Affect 2–5% of children between 6 months and 5 years. They look frightening, usually stop within 1–2 minutes and leave no damage. Lay the child on their side, put nothing in the mouth, time it. First seizure or one lasting over 5 minutes: call emergency services. Fever medicines do not prevent them.
These numbers are conversions from leaflets and guidelines. Before giving a medicine, confirm them at the source:
- NHS: paracetamol for children · NHS: ibuprofen for children
- NICE NG143 — fever in under 5s · AAP HealthyChildren.org
- Polish medicines register (URPL) — official leaflets of the products listed here
- Your own country's medicines regulator and the leaflet in the box always take precedence.
Don't want to calculate and write this down every time?
Oh Fever does it from your child's profile and the product you use: it converts the leaflet dose to weight, counts down to the next dose and watches the daily limit — on iPhone and Apple Watch. Free for one child.
Read next
NICE NG143 — Fever in under 5s
American Academy of Pediatrics — Medications used to treat fever
AAP — How to take a child's temperature
This content is for information only and does not replace your doctor or the medicine leaflet. Doses on this page are the mg/kg ranges from manufacturers' leaflets converted to body weight. Check the strength on the package before giving any medicine. For high fever, any fever in an infant under 3 months, or worrying symptoms, contact a doctor.