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Glandular fever

Glandular fever is an infection caused by a virus known as the Epstein-Barr virus. It mostly affects teenagers and young adults.

It gets better without treatment. But it can make you feel very ill and can last for weeks. It is sometimes known as infectious mononucleosis or mono.

Symptoms of glandular fever

Common symptoms of glandular fever include:

You do not usually get glandular fever more than once.

Glandular fever complications

Most people get over glandular fever with no problems. But it can lead to other illnesses.

These include:

  • lower level of blood cells such as anaemia
  • an infection such as pneumonia
  • a neurological illness such as Guillain-Barré syndrome or Bell's palsy
  • mild inflammation of the liver causing jaundice (yellowing of the skin) which usually clears up by itself

How to stop glandular fever spreading

Glandular fever is very infectious. It passes in saliva.

It can spread through:

  • kissing - it is often referred to as the 'kissing disease'
  • exposure to coughs and sneezes
  • sharing utensils, such as cups, glasses and unwashed forks and spoons

You are infectious for up to 7 weeks before you get symptoms.

To prevent glandular fever from spreading:

  • wash your hands regularly
  • wash bedding and clothes that may have saliva on them
  • do not kiss others
  • do not share cups, cutlery or towels

Non-urgent advice: Speak to a GP if you have:

  • a very high temperature (40 degrees Celsius or higher) or you feel hot and shivery
  • a severe sore throat
  • swelling on either side of your neck - swollen glands
  • extreme tiredness or exhaustion
  • tonsillitis that is not getting better
  • a pain in your tummy

Tests for glandular fever

Glandular fever symptoms are like those of strep throat (bacterial infection) or tonsillitis.

Your GP might arrange tests to confirm it's glandular fever. This would include a blood test for the Epstein-Barr virus.

Your tests may not pick up the virus if you are in the very early stage of the illness.

Emergency action required: Call 999 or 112 or go to your emergency department (ED) if you have:

  • difficulty swallowing
  • difficulty breathing
  • extreme tummy pain

Treatment for glandular fever

There's no cure for glandular fever. It gets better by itself.

You should:

  • rest and sleep
  • drink plenty of fluids to avoid dehydration
  • take painkillers like paracetamol or ibuprofen


Do not give aspirin to children under 16

Antibiotics and glandular fever

Antibiotics do not work for glandular fever. This is because glandular fever is caused by a virus. Antibiotics do not work on viruses.

Returning to normal activities after glandular fever

You should feel better within 2 to 3 weeks. Some people might feel extremely tired for months. Try to increase your activity gradually when your energy starts to come back.

Glandular fever and school or work

You can go back to school or work as soon as you start to feel better.

You can still be infectious for weeks or longer after symptoms clear up.

Glandular fever and sports

Glandular fever can cause your spleen to swell. For the first month, avoid contact sports or activities where there is a risk you could fall. This could damage your spleen. Your spleen is to the left of your tummy, under your ribs.

Glandular fever and alcohol

Do not drink any alcohol if you have glandular fever. This is because your liver might be weak while you are ill.

Content supplied by the NHS and adapted for Ireland by the HSE

Page last reviewed: 22 May 2023
Next review due: 22 May 2026

This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.