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About Stroke

	Illustration of tissue death in the frontal cut-section of the brain, as well as a blood clot that caused the damage.Stroke is a medical emergency. Know the signs and symptoms of stroke, and call 9-1-1 right away if you think someone might be having a stroke. Getting fast treatment is important to preventing death and disability from stroke.

You may be able to prevent stroke or reduce your risk through healthy lifestyle changes. In addition, medication can reduce stroke risk for some people.

To understand stroke, it helps to understand something about the brain. The brain controls our movements; stores our memories; and is the source of our thoughts, emotions, and language. The brain also controls many functions of the body, like breathing and digestion.

To work properly, your brain needs oxygen. Although your brain makes up only 2% of your body weight, it uses 20% of the oxygen you breathe.1 Your arteries deliver oxygen-rich blood to all parts of your brain.

What Happens During a Stroke

If something happens to interrupt the flow of blood, brain cells start to die within minutes because they can’t get oxygen. This is called a stroke. Sudden bleeding in the brain also can cause a stroke if it damages brain cells. A stroke can cause lasting brain damage, long-term disability, or even death.

If brain cells die or are damaged because of a stroke, symptoms of that damage start to show in the parts of the body controlled by those brain cells.

Quick Treatment Is Critical for Stroke

A stroke is a serious medical condition that requires emergency care. Call 9-1-1 immediately if you or someone you are with shows any signs of a stroke.

Learn more about the types of stroke, the signs and symptoms of a stroke, what treatments are available for stroke, and what happens after a stroke.

The following are downloadable fact sheets about stroke and related conditions:


  1. National Institute of Neurological Disorders and Stroke. The Brain: Our Sense of Self (Teacher's Guide). Web site. Accessed December 4, 2013.