Can I Take a Baby Aspirin Every Day?

For most healthy adults, taking a baby aspirin every day is no longer recommended. Guidelines shifted substantially in 2022, when the U.S. Preventive Services Task Force reversed its earlier position and recommended against starting daily low-dose aspirin for heart disease prevention in anyone 60 or older, while downgrading the recommendation for younger adults to “individual decision” territory. The reason is straightforward: a large body of trial data now shows that, for people who have never had a heart attack or stroke, the small reduction in cardiovascular events is roughly cancelled out by an increase in serious bleeding.

Why the Guidelines Changed

Until 2016, the USPSTF recommended that adults aged 50 to 59 with elevated cardiovascular risk start daily low-dose aspirin, and suggested adults 60 to 69 consider it individually. The updated 2022 recommendation replaced those age ranges and downgraded the evidence. Adults 40 to 59 with a 10-year cardiovascular risk of 10 percent or higher can still discuss it with a doctor, but the task force now recommends against initiating aspirin in adults 60 and older for primary prevention altogether.¹

The shift was driven by three large clinical trials published in 2018 that enrolled tens of thousands of participants and found little or no cardiovascular benefit from daily aspirin in people without existing heart disease, with some evidence of net harm.² These weren’t small or ambiguous studies. Combined with earlier data, they tipped the scales. A major collaborative meta-analysis had already noted that in people without previous vascular disease, aspirin’s value was “uncertain” because the reduction in blocked-artery events had to be weighed against an increase in major bleeds.³

The Benefit-Versus-Bleeding Tradeoff

The numbers tell a clear story. A meta-analysis of 13 trials covering more than 164,000 participants found that aspirin reduced composite cardiovascular events modestly, with about 60 events per 10,000 person-years in the aspirin group versus 65 in the no-aspirin group. But major bleeding events rose from about 16 per 10,000 person-years without aspirin to roughly 23 with it. In practical terms, you would need to treat about 241 people for one to avoid a cardiovascular event, while about 210 people taking aspirin would produce one extra major bleed.⁴

A separate meta-analysis focusing on more recent trial data found that aspirin cut the risk of nonfatal heart attacks by about 21 percent in otherwise healthy people or those with cardiovascular risk factors, but had no effect on cardiovascular death and raised major bleeding risk by roughly 48 percent. In people with diabetes specifically, aspirin showed no meaningful effect on heart attacks or cardiovascular death and still increased bleeding.⁵

The takeaway is not that aspirin does nothing for the heart. It does reduce nonfatal heart attacks. The problem is that the bleeding it causes is roughly proportional, and for someone who has not yet had a cardiac event, the arithmetic does not clearly favor the drug.

When Daily Aspirin Is Still the Right Call

The conversation above applies to primary prevention, meaning people who have never had a heart attack, stroke, or other diagnosed cardiovascular event. For secondary prevention, the picture is completely different. If you have already had a heart attack, been diagnosed with atherosclerotic cardiovascular disease, or had a stent placed, daily aspirin remains a standard part of treatment and its benefits are well established. A large meta-analysis described the net benefit in this group as “definite and substantial.”³

In secondary prevention, the ADAPTABLE trial compared 81 mg and 325 mg aspirin doses in patients with established cardiovascular disease and found no significant difference in effectiveness between the two doses for either men or women. Rates of death, heart attack, and stroke were similar regardless of aspirin dose or sex.⁶ So if your doctor has you on baby aspirin after a heart event, there is no evidence that a higher dose would help more.

What Bleeding Actually Looks Like

When researchers talk about aspirin’s bleeding risks, they mostly mean gastrointestinal bleeding and, less commonly, bleeding inside the skull. These are not minor concerns.

Even at low doses (100 mg or less per day, which includes the 81 mg baby aspirin), aspirin raised the risk of major gastrointestinal bleeding by about 58 percent in primary prevention studies. In absolute terms, that translated to roughly 1.4 extra major gut bleeds per 1,000 person-years of use.⁷ People who are older, male, or who have cardiovascular risk factors that also raise bleeding risk face even higher rates. A population-based study found the relative risk of upper gastrointestinal bleeding was higher in people taking aspirin for primary prevention than in those taking it for secondary prevention, suggesting that the people with the least to gain face disproportionate gut risk.⁸

Inside the skull, the numbers are smaller but the stakes are higher. A meta-analysis of eight trials found that low-dose aspirin was associated with about two additional intracranial hemorrhages per 1,000 people. The strongest signal came from subdural and extradural bleeds, where aspirin raised the risk by roughly 53 percent compared with no aspirin.⁹ In healthy adults over 70, a similar pattern appeared in the ASPREE trial, where aspirin users had a statistically significant increase in intracranial bleeding compared with those on placebo.¹⁰

Older Adults Face the Steepest Downside

The ASPREE trial deserves special attention because it enrolled more than 19,000 healthy adults aged 70 and older (65 and older for Black and Hispanic participants in the U.S.) and followed them for a median of nearly five years. Aspirin did not extend healthy, disability-free life, did not reduce dementia, and did not prevent cardiovascular disease or stroke in this group. Meanwhile, it increased gastrointestinal bleeding by about 60 percent overall, with nearly twice the rate of upper GI bleeds in the aspirin arm compared with placebo.¹¹

This trial was pivotal in pushing the USPSTF to recommend against initiating aspirin for primary prevention in people 60 and older. The combination of no meaningful cardiovascular benefit and clearly elevated bleeding risk made the case straightforward. If you are over 60, have never had a heart attack or stroke, and are taking a daily baby aspirin “just in case,” that is precisely the situation the latest guidelines advise against.

Do Not Stop Suddenly Without Talking to Your Doctor

If you have been taking daily aspirin for years, especially for secondary prevention, do not stop abruptly on your own. A large Swedish study of more than 600,000 aspirin users found that people who discontinued aspirin had a 37 percent higher rate of cardiovascular events than those who continued, corresponding to roughly one additional cardiovascular event per year for every 74 patients who stopped. The increased risk appeared shortly after stopping and did not fade over time.¹²

Research suggests aspirin withdrawal can temporarily increase the body’s tendency to form blood clots, creating a rebound period of elevated risk.¹³ If your doctor decides you should stop, they will typically plan the transition rather than having you quit cold. The point holds even for people whose primary prevention situation no longer clearly favors aspirin: stopping is a medical decision, not a DIY one.

Ibuprofen and Other Painkillers Can Block Aspirin’s Effect

One interaction that catches many people off guard involves ibuprofen and similar over-the-counter anti-inflammatory painkillers. Taking ibuprofen alongside aspirin can interfere with aspirin’s ability to prevent blood clots, because both drugs compete for the same binding site on platelets. Modeling studies predicted that taking ibuprofen within an hour after aspirin markedly reduced aspirin’s antiplatelet effect, while taking ibuprofen up to 12 hours before aspirin completely abolished it.¹⁴ Simulations of clinically realistic ibuprofen regimens confirmed that multiple daily doses of ibuprofen block aspirin’s antiplatelet effect even when the ibuprofen is taken after the aspirin.¹⁵

Real-world data have borne this out. Patients given NSAIDs alongside low-dose aspirin after joint replacement surgery had higher rates of blood clots, likely due to competitive inhibition at platelet receptor sites.¹⁶ If you rely on daily aspirin for cardiovascular protection, occasional ibuprofen for a headache probably won’t undo everything, but regular use of NSAIDs is a conversation to have with your doctor. Acetaminophen (Tylenol) does not share this interaction.

Body Weight May Affect Whether Baby Aspirin Works

A finding that gets surprisingly little public attention is that standard baby aspirin doses may not work equally well across different body sizes. An analysis of primary prevention trial data found that low-dose aspirin (100 mg or less per day) reduced cardiovascular events by about 23 percent in people weighing under 70 kg (roughly 154 pounds), but showed weaker benefit in heavier individuals. For people weighing 70 kg or more, higher doses of aspirin (300 mg or more daily) appeared to be the effective range.¹⁷

This raises the possibility that some of the underwhelming results in large prevention trials may partly reflect a mismatch between dose and body size. Most trials used a one-size-fits-all dose. It also means that if you are larger-framed and your doctor is weighing the decision, body weight is worth discussing explicitly. This is still an evolving area, and no major guideline has yet adopted weight-based dosing, but the data are suggestive enough that researchers have called for further investigation.

Enteric Coating Does Not Appear to Help

Many people choose enteric-coated baby aspirin under the assumption that the coating protects the stomach. The ADAPTABLE trial tested this directly and found no significant difference in gastrointestinal bleeding rates between enteric-coated and uncoated aspirin formulations.¹⁸ The reason is that aspirin causes most of its gastrointestinal damage not by direct contact with the stomach lining, but systemically, by suppressing protective prostaglandins throughout the body. Moving the absorption site to the small intestine does not solve that problem.

If you are at genuine risk for stomach bleeding from aspirin, a more effective strategy is co-prescribing a proton pump inhibitor (PPI). A meta-analysis found that PPIs reduced the risk of aspirin-associated upper GI ulcers by about 84 percent and bleeding by about 73 percent, without increasing cardiovascular risk.¹⁹ Guidelines already recommend PPIs for people on combined antiplatelet therapy who have a history of GI bleeding.²⁰

The Colorectal Cancer Angle

One area where daily aspirin has shown a benefit beyond heart disease is colorectal cancer prevention. Long-term randomized trial data showed that daily aspirin taken for five years or longer reduced the 20-year risk of colon cancer, with particularly strong effects on cancers in the proximal (right-sided) colon, where risk dropped by roughly 65 percent after five or more years of use. Even at doses as low as 75 mg daily, the cancer-prevention effect held up, with an absolute reduction in 20-year fatal colorectal cancer risk of about 1.8 percent.²¹

The 2016 USPSTF recommendation actually incorporated this cancer benefit into its aspirin guidance, concluding that aspirin use reduces colorectal cancer incidence after 5 to 10 years.²² Doses in the baby aspirin range appear to be as effective as higher doses for this purpose.²³ However, the 2022 updated USPSTF cardiovascular recommendation did not include cancer prevention in its scope, and as of now, no major U.S. guideline recommends starting aspirin solely for colorectal cancer prevention in the general population. It remains a consideration that may tilt the risk-benefit math for specific individuals, particularly those with a family history of colon cancer, in conversation with their physician.

Aspirin Resistance Is Real

Not everyone who takes aspirin gets the expected antiplatelet effect. In a study of patients with coronary artery disease, about 27 percent showed laboratory evidence of aspirin resistance, meaning their platelets continued to clump despite regular aspirin use. Lower aspirin doses (100 mg or less) were independently associated with higher rates of resistance. Patients who were older, female, or anemic were also more likely to be resistant.²⁴

Routine testing for aspirin resistance is not standard practice, and there is no widely accepted protocol for what to do when it is found. But it does mean that some people faithfully taking their daily baby aspirin may not be getting the clot-prevention benefit they expect. This is another reason the decision to take aspirin should be individualized rather than treated as a blanket health habit.

The Statin Factor

Part of the reason aspirin’s appeal has faded for primary prevention is that competing treatments have gotten better. Statins, blood pressure medications, and lifestyle interventions now form the backbone of cardiovascular risk reduction, and they work without the bleeding tradeoff that aspirin carries. An analysis across risk categories found that when statins were already in the picture, the additional heart attack reduction from aspirin shrank further. For every 10,000 adults at very low risk already on a statin, aspirin would prevent just one additional heart attack while causing 20 extra major bleeds.²⁵ As baseline cardiovascular risk rose, aspirin’s absolute benefit grew, but so did bleeding events, keeping the balance unfavorable for most people.

This does not mean aspirin is obsolete. For secondary prevention it remains essential, and for select primary prevention patients in the 40-to-59 age window with meaningful cardiovascular risk and low bleeding risk, it can still make sense. But the era of recommending baby aspirin to every middle-aged adult as a kind of cardiovascular insurance policy is over. The drug works, but for people who have not yet had a cardiovascular event, the math rarely adds up.