Embolism is a medical condition that occurs when a blood vessel is blocked by a substance, known as an embolus. This embolus can be a blood clot, air bubble, fat droplet, or other material that travels through the bloodstream and lodges in a vessel, disrupting normal blood flow. The most common type of embolism is a pulmonary embolism, which affects the lungs and can be life-threatening. Other types include cerebral embolism, which can lead to a stroke, and arterial embolism, which can affect various organs. Prompt diagnosis and treatment are crucial to prevent serious complications.