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Flu (influenza) is a common infectious viral illness. You can catch flu all year round, but it’s especially common in winter. This is why it’s also known as seasonal flu.

You can catch flu many times because flu viruses change regularly. Your body won’t have a natural resistance to the new versions.

Flu symptoms

Some of the main symptoms of flu include:

  • a sudden high temperature
  • tiredness and weakness
  • a headache
  • general aches and pains
  • a dry, chesty cough
  • sore throat
  • difficulty sleeping
  • loss of appetite
  • diarrhoea or tummy pain
  • feeling sick and being sick
  • chills
  • a runny or blocked nose
  • sneezing

The symptoms are similar for children. They may also get pain in their ear and be less active.

How long do symptoms last

The symptoms of flu usually develop 1 to 3 days after becoming infected. Most people will feel better within a week.

But, you may have a lingering cough and still feel very tired for a few more weeks.

Flu-like illness self-help guide

Complete our self-help guide to check your symptoms and find out what to do next.

Phone 999 or go to A&E if you:

  • get sudden chest pain
  • have difficulty breathing
  • start coughing up a lot of blood

Phone 111 or ask for an urgent GP appointment if:

You or your child have symptoms of flu and:

  • you’re worried about your baby’s or child’s symptoms
  • you’re 65 or over
  • you’re pregnant
  • you have a long-term medical condition – for example, diabetes or a condition that affects your heart, lungs, kidneys, brain or nerves
  • you have a weakened immune system – for example, because of chemotherapy or HIV
  • your symptoms don’t improve after 7 days

Get advice from a pharmacist

A pharmacist can give you advice about how to treat flu.

Treating flu at home

If you have flu, there are things you can do to help you recover more quickly.


  • rest
  • get plenty of sleep
  • keep warm
  • drink lots of water to avoid dehydration
  • take paracetamol or ibuprofen to lower your temperature and treat aches and pains
  • stay off work or school until you feel better


  • do not take paracetamol and flu remedies that contain paracetamol at the same time

GPs don’t recommend antibiotics for flu. They won’t relieve your symptoms or speed up your recovery.

Preventing the spread of flu

Flu is spread by germs from coughs and sneezes. These can live on hands and surfaces for 24 hours.

You can help stop yourself catching flu or spreading it to others with good hygiene measures.


  • wash your hands regularly with soap and warm water
  • clean surfaces like your computer keyboard, telephone and door handles regularly
  • use tissues to cover your mouth and nose when you cough or sneeze
  • bin used tissues as soon as possible
  • avoid unnecessary contact with other people while you’re infectious
  • stay off work or school until you’re feeling better

How to wash your hands properly

Help to keep germs at bay by washing your hands properly. 

The difference between flu and a cold

It can sometimes be difficult to tell if you have flu or a cold.

Flu symptoms:

  • come on quickly
  • usually include fever and aching muscles
  • are more severe

Cold symptoms:

  • come on gradually
  • mainly affect your nose and throat
  • are fairly mild, so you can still get around and are usually well enough to go to work

Flu vaccine

The annual flu vaccine can help reduce your risk of getting flu each year.

It’s offered every year for free by the NHS to help protect people at risk of flu and its complications.

Further information about the flu vaccine for adults

Further information about the flu vaccine for children

Last updated:
04 December 2023

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