Blood clots
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Definition
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By Mayo Clinic Staff
Blood clots are gel-like clumps of blood. They are beneficial when they form in response to an injury or a cut, plugging the injured blood vessel, which stops bleeding.
Some blood clots form inside your veins without a good reason and don't dissolve naturally. These may require medical attention, especially if they are in your legs or are in more critical locations, such as your lungs and brain. A number of conditions can cause this type of blood clot.
https://www.mayoclinic.org/symptoms/blood-clots/basics/definition/sym-20050850
