When a cough after a cold or flu starts coming from deep in your chest with mucus, it may be a chest infection. The NHS says chest infections often come after colds or flu and usually get better on their own in about 7 to 10 days, though the cough and mucus can last up to 3 weeks. At home it says rest, drink lots of water, and raise your head with extra pillows when sleeping. See a GP if you feel very unwell or get worse, cough up blood, or have had a cough for more than 3 weeks. This sets out the NHS page “Chest infection”.
1. It usually gets better in about 7 to 10 days. The cough and mucus can last up to 3 weeks.
2. Rest, drink plenty of water, raise your head with pillows. Antibiotics won’t help if a virus is the cause.
3. Very unwell or worse, coughing up blood, or a cough over 3 weeks: see a GP — also if you’re pregnant, 65 or over, have a weakened immune system or a long-term heart, lung or kidney condition.
Symptoms — NHS
The NHS lists a chesty cough (you may cough up green or yellow mucus), wheezing and shortness of breath, chest pain or discomfort, a high temperature, headache, aching muscles and tiredness. It says chest infections often follow colds or flu.
What to do and not do at home — NHS
| Type | What the NHS says | Worth noting (ours) |
|---|---|---|
| Do | Get plenty of rest | — |
| Do | Drink lots of water to loosen the mucus | — |
| Do | Raise your head with extra pillows when sleeping | Said to make breathing easier and clear your chest of mucus |
| Do | Use painkillers for fever, headache and muscle pain | Choosing one: OTC medicine by symptom |
| Do | A hot lemon and honey drink for a sore throat | No honey for children under 12 months |
| Don’t | Let children breathe in steam from a bowl of hot water | Risk of scalding (our gloss) |
| Don’t | Give aspirin to children under 16 | — |
| Don’t | Smoke | Said to make symptoms worse |
A pharmacist can suggest cough medicines that loosen mucus, but they are not suitable for children under 6. Choosing a painkiller is in OTC medicine by symptom; the NHS thresholds for a cough itself are in cough.
When to see a GP — NHS
| If | Where | Worth noting (ours) |
|---|---|---|
| You feel very unwell or symptoms get worse | GP | — |
| You cough up blood | GP | — |
| You’ve had a cough for more than 3 weeks | GP | Same line as the cough and mucus lasting up to 3 weeks |
| You’re pregnant or 65 or over | GP | — |
| You have a weakened immune system or a long-term heart, lung or kidney condition | GP | — |
The NHS says you may have pneumonia if your symptoms are severe (pneumonia). This page has no 999 or A&E list; all of the rows above sit under “non-urgent: see a GP”.
Causes and treatment — NHS
| Cause | Example | Treatment |
|---|---|---|
| Virus | Viral bronchitis | Usually clears up by itself after a few weeks — antibiotics won’t help |
| Bacteria | Bacterial infections such as pneumonia | A GP may prescribe antibiotics — complete the whole course as advised by the GP |
A blood test or a mucus sample may be needed to find the cause, the page says.
Avoiding spreading it — NHS
- Cover your mouth when you cough or sneeze
- Wash your hands often — see handwashing
- Throw away used tissues straight away
- If you have a high temperature or don’t feel well enough for normal activities, stay at home and avoid contact with other people
People at higher risk may be advised to have the yearly flu vaccine and the pneumococcal vaccine, which helps prevent pneumonia; stopping smoking and cutting down on alcohol also help. This year’s flu schedule is in flu vaccine.
Checklist
- ☐ Rest, plenty of water, raise your head with pillows
- ☐ No honey under 12 months; no aspirin under 16
- ☐ No cough medicine under 6
- ☐ Blood in the cough, a cough over 3 weeks, or getting worse: GP
- ☐ Pregnant, 65 or over, weakened immunity or long-term condition: see a GP early
Questions that remain
Do I need antibiotics?
The NHS says antibiotics won’t help if a virus is the cause. For a bacterial infection a GP may prescribe them, and you should finish the course as advised.
It’s been 10 days and I still have a cough.
The cough and mucus can last up to 3 weeks. Past 3 weeks, with blood, or if you get worse, see a GP.
Sources
- NHS — Chest infection — source (page shows: reviewed 21 June 2023, next review 21 June 2026 — the review date has passed and we quote the page as shown; checked 19 October 2026). Symptoms, recovery time, 5 dos and 3 don’ts, pharmacist, 5 GP reasons, causes and treatment, avoiding spread, vaccines.
- Not read. Korean agency guidance on chest infections or bronchitis.
- What we added. The “worth noting” column and the Korean care gloss.
Where else to check
- Your GP or an internal medicine clinic — a cough over 3 weeks, blood in it, or getting worse.
Written on 19 October 2026. The content is from the NHS; the glosses are ours.
