A stroke occurs when blood flow to the brain is interrupted by a blocked or burst blood vessel. There are two main types of stroke - ischemic, caused by a clot blocking a vessel, and hemorrhagic, caused by a ruptured vessel. The goal of acute stroke treatment is to rapidly restore blood flow to the brain to rescue tissue at risk of further damage. Treatment depends on the type and severity of stroke, and may involve clot-busting drugs, blood thinners, surgery, or rehabilitation therapies to help recovery.