Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Lung Disease & Respiratory Health Center

Font Size

Pulmonary Embolism - Cause

Pulmonary embolism is caused by a blocked artery in the lungs. The most common cause of such a blockage is a blood clot that forms in a deep vein in the leg and travels to the lungs, where it becomes lodged in a smaller lung artery.

Almost all blood clots that cause pulmonary embolism are formed in the deep leg veins. Clots also can form in the deep veins of the arms or pelvis.

Recommended Related to Lung Disease/Respiratory Problems

Is Bronchitis Contagious?

Bronchitis makes you cough -- a lot. It can make it hard to breathe, too, and can cause wheezing, fever, tiredness, and chest pain. The disease happens when the lining of the airways in your lungs gets irritated.

Read the Is Bronchitis Contagious? article > >

Sometimes blood clots develop in surface veins. But these clots rarely lead to pulmonary embolism.

In rare cases, pulmonary embolism may be caused by other substances, including:

  • Small masses of infectious material.
  • Fat, which can be released into the bloodstream after some types of bone fractures, surgery, trauma, or severe burns.
  • Air bubbles or substances that get into the blood from trauma, surgery, or medical procedures.
  • Tumors caused by rapidly growing cancer cells.

    WebMD Medical Reference from Healthwise

    Last Updated: September 09, 2014
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
    Next Article:

    Today on WebMD

    man coughing
    You may not even know you have it.
    blood clot
    Signs of this potentially fatal complication.
    man coughing
    When a cold becomes bronchitis.
    human lungs
    Causes behind painful breathing, fluid buildup.

    chest x-ray
    Bronchitis Overview
    Copd Myth Fact Quiz
    Energy Boosting Foods

    woman coughing
    Lung xray and caduceus