Pulmonary embolism

A pulmonary embolism is when a blood clot blocks a blood vessel in your lungs. It can be life-threatening if not treated quickly.

Check if you have a pulmonary embolism

Symptoms of a pulmonary embolism include:

You may also have pain, redness and swelling in one of your legs (usually the calf). These are symptoms of a blood clot, also called DVT (deep vein thrombosis).

Urgent advice: Ask for an urgent GP appointment or get help from NHS 111 if:

  • you have difficulty breathing which comes on suddenly
  • you're coughing up blood

You can call 111 or get help from 111 online.

Immediate action required: Call 999 or go to A&E if:

  • you have severe difficulty breathing
  • you feel pain in your chest or upper back
  • your heart is beating very fast
  • someone has passed out

These could be signs of a pulmonary embolism or another serious condition.

Treating a pulmonary embolism

If a GP thinks you've got a pulmonary embolism, you'll be sent to hospital for further tests and treatment.

At hospital, you'll probably be given an injection of anticoagulant medicine before you get any test results.

Anticoagulants stop blood clots getting bigger and prevent new clots forming.

If tests confirm you have a pulmonary embolism, you'll continue with anticoagulant injections for at least 5 days.

You'll also need to take anticoagulant tablets for at least 3 months.

You should make a full recovery from a pulmonary embolism if it's spotted and treated early.

Reduce your pulmonary embolism risk

A pulmonary embolism often happens when part of the blood clot dislodges itself from your leg and travels up to your lungs, causing a blockage.

There are measures you can take to lower your risk of getting a pulmonary embolism.

If you're being treated in hospital for another condition, your medical team should take steps to prevent DVT (deep vein thrombosis).

A DVT can occasionally develop on long journeys such as bus, train or air travel. The risk of developing DVT is increased for flights lasting more than 4 hours.

There are things you can do to reduce your risk of getting a travel-related DVT.


  • sit comfortably in your seat and choose an aisle seat if possible

  • wear loose-fitting clothing

  • make sure you have plenty of leg room

  • drink water regularly

  • take regular breaks from sitting

  • bend and straighten your legs, feet and toes every 30 minutes while seated

  • press the balls of your feet down hard against the floor every so often

  • wear flight socks


  • do not sit for long periods without moving

  • do not drink alcohol

  • do not drink too much coffee and other caffeine-based drinks

  • do not take sleeping pills

Page last reviewed: 25 May 2023
Next review due: 25 May 2026