Aspirin to Prevent Heart Attack and Stroke


Aspirin prevents blood clots from forming in the arteries. Doctors sometimes recommend daily aspirin for people at high risk of heart attack or stroke.

But taking aspirin isn't right for everyone, because it can cause serious bleeding. You and your doctor can decide if aspirin is a good choice for you.

Who should take aspirin

For people who have had a heart attack: Aspirin can help prevent a second heart attack. Your doctor has probably already prescribed aspirin for you.

For people who have had a stroke: Aspirin can help prevent a second stroke or a transient ischemic attack (TIA), which is often a warning sign of a stroke.

For people who have never had a heart attack or stroke: Talk to your doctor before you start taking aspirin every day. Aspirin lowers the risk of heart attack and stroke. But aspirin can also cause serious bleeding. You and your doctor can decide if aspirin is a good choice for you based on your risk of a heart attack and stroke and your risk of serious bleeding.

Aspirin may also be used by people who:

Who should not take aspirin

Experts recommend that most people who have never had a heart attack or stroke should not take aspirin. That's because for people who aren't at high risk of heart problems, the chance of bleeding from taking aspirin tends to outweigh the benefits.

Also, people who have certain health problems shouldn't take aspirin. These include people who:

  • Have a stomach ulcer.
  • Have recently had a stroke caused by bleeding in the brain.
  • Have other health problems that increase their risk of bleeding.
  • Are allergic to aspirin.
  • Have asthma that is made worse by aspirin.

How do you take aspirin safely?

  • Take aspirin with food.

    If aspirin upsets your stomach, you can try taking it with food. But if that doesn't help, talk with your doctor. Aspirin can irritate the stomach lining and sometimes cause serious problems.

  • Talk to a doctor before a surgery or procedure

    Before you have a surgery or procedure that may cause bleeding, tell your doctor or dentist that you take aspirin. Aspirin may cause you to bleed more than usual. He or she will tell you if you should stop taking aspirin before your surgery or procedure. Make sure that you understand exactly what your doctor wants you to do.

  • Do not suddenly stop taking aspirin.

    Do not suddenly stop taking aspirin without talking to your doctor first. Talking to your cardiologist first is especially important if you have had a stent placed in a coronary artery.

  • Seek help for signs of serious bleeding.

    Call your doctor now or seek immediate medical care if you have any abnormal bleeding, such as:

    • A nosebleed that you can't easily stop.
    • Bloody or black stools, or rectal bleeding.
    • Bloody or pink urine.
  • Tell your doctor about all your medicines.

    Aspirin should not be taken with many prescription and over-the-counter drugs, vitamins, herbal remedies, and supplements. So before you start aspirin therapy, talk to your doctor about all the drugs and other remedies you take.

  • Be careful taking pain relievers.

    Although nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen relieve pain and inflammation much like aspirin does, they do not affect blood clotting in the same way that aspirin does. Do not substitute NSAIDs for aspirin. NSAIDs may increase your risk for a heart attack or stroke.

  • Take NSAIDs safely.

    If you need both aspirin and an NSAID pain reliever every day, talk to your doctor first. Ask your doctor what pain reliever you should take. You may be able to use another type of pain reliever, such as acetaminophen, to treat your pain.

    If you take an NSAID every day, your doctor may recommend that you take the NSAID and aspirin pills at different times. If you take these pills at the same time, aspirin might not work as well to prevent a heart attack or stroke. Do not take the NSAID pill during either the 8 hours before or the 30 minutes after you take aspirin. Here's an example: Take your aspirin. Wait 30 minutes. Then take your NSAID.

    If you take an NSAID once in a while, it does not seem to cause problems with aspirin.

  • Discuss alcohol with your doctor.

    Ask your doctor if you can drink alcohol while you take aspirin. And ask how much you can drink. Too much alcohol with aspirin can cause stomach bleeding.

  • Talk to your doctor if you are pregnant.

    If you are pregnant, do not take aspirin unless your doctor says it is okay.

How do you take it?

Talk to your doctor before taking daily aspirin. It's not right for everyone.

If you and your doctor decide that daily aspirin is right for you, your doctor will recommend a dose of aspirin and how often to take it. Low-dose aspirin (81 mg) is the most common dose used to prevent a heart attack or a stroke. A typical schedule is to take aspirin every day. Be sure you know what dose of aspirin to take and how often to take it.

Aspirin can cause serious bleeding. Be sure you get instructions about how to take aspirin safely.

How can aspirin prevent a heart attack or stroke?

Aspirin slows the blood's clotting action by reducing the clumping of platelets. Platelets are cells that clump together and help to form blood clots. Aspirin keeps platelets from clumping together, thus helping to prevent or reduce blood clots.

Most heart attacks and strokes are caused by blood clots. Blood clots can form in arteries and block the flow of oxygen-rich blood to the heart muscle or part of the brain.

When taken daily after having a heart attack or stroke, aspirin helps prevent dangerous clots from happening again.

Daily aspirin may also be helpful for preventing clots in some people who are at high risk for a heart attack or stroke if they are also at low risk of bleeding problems, which can happen more while taking aspirin because it reduces clots. That's why it's important to talk to your doctor before starting daily aspirin.



  1. Arnett DK, et al. (2019). 2019 ACC/AHA guideline on the primary prevention of cardiovascular disease. Circulation, published online March 17, 2019: CIR0000000000000678. DOI: 10.1161/CIR.0000000000000678. Accessed March 26, 2019. [Erratum in Circulation, 140(11): e649–e650. DOI: 10.1161/CIR.0000000000000725. Accessed September 10, 2019.]
  2. Zheng SL, Roddick AJ (2019). Association of aspirin use for primary prevention with cardiovascular events and bleeding events: A systematic review and meta-analysis. JAMA, 321(3): 277–287. DOI: 10.1001/jama.2018.20578. Accessed April 30, 2019.


Current as of: June 24, 2023

Author: Healthwise Staff
Clinical Review Board
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