What happens when you get blood clots?

when a clot obstructs an artery (or thrombus) and thus prevents the flow of blood and oxygen to an organ, this can create a tissue injury, ie, an infarct. When blood clots break off (embolism) from the area they need to protect, they can put other organs at risk.

Clots that obstruct blood flow are the main cause of most strokes and heart attacks.