Heart attack: Should I take daily aspirin to prevent a heart attack or stroke?

Aspirin can prevent blood clots from forming in your arteries.

People who have heart disease are at risk for a heart attack or a stroke. A fatty substance called plaque builds up in their arteries and narrows them. Sometimes a piece of plaque breaks open and causes a clot to form. If the clot blocks blood flow to your artery, it can cause you to have a heart attack or a stroke.

A blood clot in an artery in your heart can cause a heart attack. A clot in an artery in your brain or neck can cause a stroke.

For more information on heart disease, see the topic Coronary Artery Disease.

For more information on stroke, see the topic Stroke.

You may have a higher risk of having a heart attack or a stroke if:

• You have high blood pressure .
• You have high cholesterol .
• You have low levels of HDL cholesterol , or the "good" cholesterol. HDL helps prevent cholesterol from building up in your arteries.
• You have diabetes and are at risk of heart disease.
• You have a family history of early heart disease .
• You smoke.

Your age can also increase your chance of having a heart attack or a stroke. Men older than 45 and women older than 55 have a higher risk.

If you know your blood pressure and cholesterol numbers, you can use this Interactive Tool: Are You at Risk for a Heart Attack? to find out your risk. Show the results to your doctor so you can talk about whether aspirin might be a good choice for you.

Doctors use different guidelines to decide who should take daily aspirin. But no matter which guideline your doctor follows, he or she will look at your health and at your risk for a heart attack or stroke. Then you and your doctor will balance the benefits and the risks of taking a daily aspirin to see if a daily aspirin is right for you.

Some people shouldn't take aspirin. These include people who:

• Have a stomach ulcer.
• Have recently had a stroke caused by bleeding in the brain.
• Are allergic to aspirin.
• Have high blood pressure that isn't under control.
• Have asthma that is made worse by aspirin.

Gout can become worse or hard to treat for some people who take low-dose aspirin.

If you can't take aspirin, your doctor may have you take clopidogrel (Plavix) to help prevent a heart attack or a stroke.

Daily aspirin isn't advised for people who have a low risk of heart attack or stroke.

Aspirin reduces your chance of having a heart attack . It also reduces the chance of a stroke or a "mini-stroke." A mini-stroke is also called a TIA .

Daily aspirin can benefit men and women who have never had a heart attack or stroke. But the benefits seem to differ by gender. For men, aspirin seems to work better to prevent a heart attack. And for women, aspirin seems to work better to prevent a stroke.

Even if you take aspirin every day, you still need to follow a healthy lifestyle. Here are some steps you can take to reduce your chance of having a heart attack or a stroke:

• Eat healthy foods.
• Get regular exercise.
• Keep your blood pressure and cholesterol levels under control.
• Don't smoke.

Aspirin is usually very safe. But there is a higher chance of bleeding when you take it every day. You'll have to weigh this risk against the benefits of taking aspirin to prevent a heart attack or a stroke.

A stroke caused by bleeding in the brain is the most serious side effect of aspirin. But this is very rare. It happens in less than 1 out of 1,000 people who take aspirin. ¹ This means that more than 999 out of 1,000 people who take aspirin don't have a stroke caused by bleeding in the brain.

Aspirin can also cause your stomach or another part of your digestive tract to bleed. Bleeding that is bad enough to need treatment in a hospital happens in 1 to 2 out of 1,000 people who take aspirin. ¹ This means that 998 to 999 out of 1,000 people who take aspirin don't have serious bleeding.

Even though most people will take aspirin every day to help prevent a heart attack or a stroke, others may be advised to take aspirin every other day.

The dose for daily aspirin ranges from 75 mg to 325 mg. One adult-strength aspirin contains about 325 mg. One low-dose aspirin contains 81 mg. Low-dose aspirin is the most common dose used to prevent a heart attack or a stroke.

Your doctor may advise you to take daily aspirin if:

• Your chance of having a heart attack or a stroke is higher than average. You can use this Interactive Tool: Are You at Risk for a Heart Attack? to find out your risk.
• You have one or more risk factors for heart disease or stroke, such as diabetes, high blood pressure, high cholesterol, smoking, or a family history of early heart disease or stroke.