Key takeaways:
Aspirin isn’t commonly known to affect blood pressure. But it does come with a higher risk of bleeding.
There are a few groups of people who may benefit from taking low-dose aspirin (81 mg per day). This includes people who’ve previously had a heart attack or stroke. But you shouldn’t start aspirin without talking to a healthcare professional first.
The risks of taking aspirin may outweigh the benefits in many people. This usually includes people who haven’t had a heart attack or stroke and are at low risk of heart disease. It also includes people who have a high risk of bleeding.
Save on related medications
Hypertension (high blood pressure) is a common medical condition. It affects half of U.S. adults. Although certain groups of people — including older adults and African Americans — are more likely to experience hypertension, it’s a health condition that can happen to anyone.
Most people with hypertension don’t have symptoms. But it can lead to serious medical problems, including heart disease or a stroke, if it isn’t treated. These are some of the most common causes of death in the U.S.
Many medications treat high blood pressure, and you may have wondered if aspirin is one of them. The answer, though, is somewhat complicated.
Does aspirin lower blood pressure?
Overall, aspirin hasn’t been found to consistently lower blood pressure. Some older research showed that low-dose aspirin (81 mg per day) may lower blood pressure when it’s taken before bedtime. But recent research has found that aspirin has no effect on blood pressure at all. Therefore, low-dose aspirin isn’t a recommended medication for lowering blood pressure in people with hypertension.
Many other medications are better studied and have been proven to lower blood pressure. If you have hypertension, a healthcare professional will likely recommend a medication that's been FDA approved to treat it. Some examples include:
Thiazide diuretics: Thiazide diuretics include hydrochlorothiazide and chlorthalidone.
Angiotensin-converting enzyme (ACE) inhibitors: ACE inhibitors include lisinopril (Zestril), enalapril (Vasotec), and benazepril (Lotensin).
Angiotensin II receptor blockers (ARBs): ARBs include losartan (Cozaar), valsartan (Diovan), irbesartan (Avapro).
Calcium channel blockers: Calcium channel blockers include amlodipine (Norvasc), verapamil (Calan), and diltiazem (Cardizem).
Beta blockers: Beta blockers include atenolol (Tenormin), carvedilol (Coreg), and metoprolol (Lopressor).
What does aspirin do in the body?
Aspirin is part of a group of medications called nonsteroidal anti-inflammatory drugs (NSAIDs). It works by blocking two enzymes (proteins): cyclooxygenase-1 and -2 (COX-1 and COX-2).
COX-1 and COX-2 are responsible for making prostaglandins. Prostaglandins are chemicals your body releases when you experience an injury or your cells get damaged.
Your body may respond to prostaglandins in a few ways, including:
Inflammation
Swelling
Pain
Fever
By blocking COX-1 and COX-2, aspirin helps relieve these symptoms.
Low-dose aspirin can also help prevent cardiovascular disease. Cardiovascular disease is a group of medical conditions that affect the heart and blood vessels. Having cardiovascular disease makes it more likely that you’ll have a heart attack or stroke.
Taking low-dose aspirin can help some people avoid these life-threatening events, by preventing blood clots. Aspirin does this by preventing platelets (blood cells that help form clots to stop bleeding) from clumping together. Although clotting can be a good thing, abnormal clotting can prevent blood from reaching your heart or brain.
Blood clots in your heart can lead to a heart attack. And clots in your brain can cause a stroke. So, for some people, taking low-dose aspirin daily is beneficial.
How do I know if low-dose aspirin is right for me?
Always talk to a healthcare professional before starting low-dose aspirin. Even though it’s available over the counter, the risks outweigh the benefits for people who don’t really need it. There are a few groups of people that may benefit from low-dose aspirin, so a healthcare professional may still recommend it. More on this next.
Heart attack and stroke prevention in certain people
The U.S. Preventive Services Task Force (USPSTF) recommends that healthcare professionals consider daily low-dose aspirin to prevent cardiovascular disease in certain groups of people. These groups include:
People who’ve had a heart attack, stroke, atrial fibrillation, or vascular stenting in the past
Adults ages 40 to 59, who have a high risk of cardiovascular disease and a low risk of bleeding
A healthcare professional can help you use a risk estimator to figure out your chances of developing cardiovascular disease. They can also talk to you about whether you have a higher bleeding risk.
If you think you qualify for low-dose aspirin treatment, talk to your healthcare team. They can help you figure out if you’re a good candidate based on your medical history, personal preferences, and risk factors for cardiovascular disease.
Preeclampsia
Preeclampsia is a medical condition where high blood pressure and abnormally high protein in the urine occurs during pregnancy. In severe cases, it can lead to organ damage in the pregnant mother and growth problems in the developing baby.
Preeclampsia can also put the pregnant mother at risk of heart problems in the future. A large review of studies, which included over 250,000 pregnant women with preeclampsia, found that having preeclampsia made you twice as likely to have heart disease or a stroke later in life. Because of this, the USPSTF recommends starting low-dose aspirin after 12 weeks of pregnancy in people who are at high risk of preeclampsia.
People who have diabetes or chronic hypertension, or those who’ve had preeclampsia in a previous pregnancy, are at the highest risk for preeclampsia.
Additional risk factors include:
Pregnancy with more than one baby
People who’ve used assisted reproductive technology (ART) to become pregnant
Kidney disease
Autoimmune disease, like lupus
The American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine have similar recommendations. For pregnant women at high risk of preeclampsia, they recommend taking low-dose aspirin, starting between 12 and 28 weeks of pregnancy. The optimal time to start low-dose aspirin, according to these organizations, is before 16 weeks.
Keep in mind there are many other risk factors for preeclampsia besides what’s listed here.
If you’re pregnant and unsure if you should take aspirin, talk to your OB-GYN physician. They can help you decide whether low-dose aspirin is a good option for you during pregnancy.
Other reasons a healthcare professional may recommend aspirin
Most people take low-dose aspirin to prevent heart attack and stroke, or if they’re experiencing preeclampsia. But a healthcare professional might recommend low-dose aspirin for other reasons. For example, low-dose aspirin may help prevent repeat pregnancy loss.
But no matter your situation, don’t start low-dose aspirin without talking to your healthcare team. It can be hard to figure out on your own whether you need low-dose aspirin. Your provider can help you decide if it’s beneficial.
What are the side effects of aspirin?
Aspirin can have both mild and more severe side effects.
Mild side effects may include:
Nausea and upset stomach
Loss of appetite
Headache
More serious side effects include:
Kidney problems
Stomach ulcers
Reye’s syndrome in children
Skin reactions
Keep in mind that certain groups of people are at higher risk of side effects when taking aspirin. For example, people at higher risk of bleeding with aspirin include:
Those who smoke
People who take other medications that can cause bleeding
Adults 60 years old or older
Seek immediate medical care if you have any signs of serious side effects from aspirin, including:
Unusual bruising
Blood in your stool
A painful peeling rash
Frequently asked questions
No, research shows that aspirin doesn’t affect blood pressure at all. It has other benefits for heart health in those at high risk for heart attack or stroke, without affecting blood pressure. If you have high blood pressure, a healthcare professional will prescribe blood pressure medications to lower it.
Yes, aspirin can be used safely in some pregnant women. It’s sometimes prescribed as a treatment for pregnant women at risk for preeclampsia or pregnancy loss. You shouldn’t start aspirin without specific medical guidance, though. Your healthcare team will let you know if you should be taking aspirin, as well as when to start.
No, research shows that aspirin doesn’t affect blood pressure at all. It has other benefits for heart health in those at high risk for heart attack or stroke, without affecting blood pressure. If you have high blood pressure, a healthcare professional will prescribe blood pressure medications to lower it.
Yes, aspirin can be used safely in some pregnant women. It’s sometimes prescribed as a treatment for pregnant women at risk for preeclampsia or pregnancy loss. You shouldn’t start aspirin without specific medical guidance, though. Your healthcare team will let you know if you should be taking aspirin, as well as when to start.
The bottom line
Aspirin isn’t considered a first-choice option for treating high blood pressure. But it can be a helpful medication for preventing heart-related problems (like heart attack) and stroke in some people. This includes people who’ve had a prior heart attack or stroke. It also includes adults ages 40 to 59 who have a low risk of bleeding and a high risk for cardiovascular disease.
But, for many people, the risks of aspirin outweigh its benefits. This includes people over 60 years old who’ve never had a heart attack or stroke. It also includes people at a high risk for bleeding. Talk to your healthcare provider if you’re wondering if you should take aspirin. They can help you weigh the risks and benefits.
Why trust our experts?
References
American College of Cardiology. (n.d.). ASCVD risk estimator.
American Heart Association. (2022). New USPSTF guidance: Continue to take low-dose aspirin if you have a history of heart attack, AFib, stroke or vascular stenting.
Bryant, A. S., et al. (2021). Low-dose aspirin use for the prevention of preeclampsia and related morbidity and mortality. American College of Obstetricians and Gynecologists.
Centers for Disease Control and Prevention. (2021). Facts about hypertension.
Costa, A. C., et al. (2017). Aspirin and blood pressure: Effects when used alone or in combination with antihypertensive drugs. Revista Purtuguesa de Cardiologia.
Hermida, R. C., et al. (2005). Aspirin administered at bedtime, but not on awakening, has an effect on ambulatory blood pressure in hypertensive patients. Journal of the American College of Cardiology.
Ittaman, S. V., et al. (2014). The role of aspirin in the prevention of cardiovascular disease. Clinical Medicine & Research.
Jones, D. W., et al. (2025). 2025 AHA/ACC/AANP/AAPA/ABC/ACCP/ACPM/AGS/AMA/ASPC/NMA/PCNA/SGIM guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: A report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation.
Li, Z., et al. (2024). Effect of aspirin on blood pressure in hypertensive patients: A systematic review and meta-analysis. BMC Cardiovascular Disorders.
National Institutes of Health. (2021). Low-dose aspirin may improve pregnancy chances for women with one or two prior miscarriages.
Obstetrics & Gynecology. (2018). ACOG committee opinion no. 743: Low-dose aspirin use during pregnancy.
U.S. Food and Drug Administration. (2024). High blood pressure — Understanding the silent killer.
U.S. Preventive Services Task Force. (2022). Aspirin use to prevent cardiovascular disease. JAMA.
U.S. Preventive Services Task Force. (2022). Aspirin use to prevent cardiovascular disease: Preventive medication.
U.S. Preventive Services Task Force. (2021). Aspirin use to prevent preeclampsia and related morbidity and mortality. JAMA.
World Health Organization. (2021). Cardiovascular diseases (CVDs).
Wu, P., et al. (2017). Preeclampsia and future cardiovascular health. Circulation: Cardiovascular Quality and Outcomes.
