A clot occurs when blood, which is usually liquid and flowing, thickens, becomes more gelatinous, and forms a clump. This is ...

Arterial thrombosis occurs when a blood clot forms in an artery. It can have life threatening consequences. Learn more.

Coronary thrombosis is an emergency, and a person should contact emergency services as soon as possible if they have symptoms of a heart attack. Learn more here.

A pulmonary embolism is a blood clot that occurs in the lungs. It can damage part of the lung and other organs and decrease oxygen levels in the blood.

Thrombosis generally has no symptoms until the clot stops or significantly decreases blood flow. When you notice symptoms, you should seek medical attention quickly.

Blood clots have been reported in a small minority of people after receiving COVID-19 vaccines by AstraZeneca and Johnson & Johnson.

Blood clots are dangerous because they can impede or block blood flow to vital organs. Here's what to know about the signs and symptoms of blood clots.

Different types of blood clots bring different kinds of symptoms. Doctors explain what you might experience if you have a blood clot.

What is a saddle pulmonary embolism? Saddle PE is when a large blood clot (thrombus) gets stuck where the main pulmonary artery branches off into a Y-shape to go into each lung.

When an artery in your lung gets blocked by a blood clot, you have a pulmonary embolism (PE). Symptoms can vary.

Blood clotting is usually a good thing. But if clots form when they shouldn’t and restrict blood flow to vital organs, they can be life-threatening.