Bayer aspirin is used to relieve everyday pain, reduce fever, and lower inflammation. At low doses, it also helps prevent repeat heart attacks and strokes in people who already have cardiovascular disease. Those two broad categories, pain relief and heart protection, cover the main reasons people reach for it.
Pain and Fever Relief
As an over-the-counter pain reliever, Bayer aspirin treats the kinds of discomfort most people deal with regularly: headaches, muscle aches, toothaches, menstrual cramps, minor arthritis pain, and the general achiness that comes with a cold or flu. It also brings down a fever. For these short-term uses, the standard dose is 325 mg or higher (Bayer sells a regular-strength 325 mg tablet and an extra-strength version).
Aspirin works by blocking the production of chemicals called prostaglandins, which your body releases in response to injury or illness. Prostaglandins trigger pain signals, drive inflammation, and raise your body temperature. By shutting down the enzyme responsible for making them, aspirin dials all three of those responses down at once.
Heart Attack and Stroke Prevention
Low-dose aspirin (typically 81 mg per day) is widely used to reduce the risk of a second heart attack or stroke. It does this by permanently disabling platelets, the tiny blood cells responsible for clotting. Platelets normally clump together at the site of a damaged blood vessel, but in people with narrowed or diseased arteries, that clumping can form a clot that blocks blood flow entirely. Because platelets can’t repair themselves once aspirin has altered them, the anti-clotting effect lasts for the entire lifespan of each platelet, roughly 7 to 10 days.
This benefit is well established for people who have already had a heart attack, stroke, or who have known blood vessel disease in the heart. For people without those conditions, the picture is very different. The FDA has stated plainly that aspirin “does not seem to work in people with healthier hearts and blood vessels,” and most health professionals agree that long-term daily aspirin for otherwise healthy people is unnecessary.
The U.S. Preventive Services Task Force updated its guidelines to reflect this. For adults 60 and older, the task force now recommends against starting a daily aspirin regimen for primary prevention of heart disease. For adults 40 to 59 with a 10% or greater 10-year cardiovascular risk, daily aspirin is a judgment call: the net benefit is small, and it only makes sense for people who are not at increased risk of bleeding. Even among those who do start, modeling data suggest it may be reasonable to stop around age 75, when bleeding risks climb.
Emergency Use During a Suspected Heart Attack
If you or someone nearby is experiencing symptoms of a heart attack, chewing a full 325 mg aspirin tablet after calling 911 is a common first-aid step. Chewing matters here because it gets the drug into your bloodstream faster than swallowing a whole tablet. The 911 operator can help you decide whether aspirin is safe in that moment, particularly if there’s an aspirin allergy or a condition that makes it risky.
Coated vs. Regular Tablets
Bayer sells both enteric-coated (“safety coated”) and regular aspirin. The coated version has a smooth shell that resists stomach acid, allowing the tablet to dissolve in the intestine instead. Many people assume this protects the stomach lining, and doctors have historically recommended it for that reason. Research from Harvard Health, however, found that coated aspirin offered no advantage over uncoated pills when it came to preventing major bleeding episodes. Both forms were equally effective at preventing heart attacks and strokes, too. The coating may reduce mild stomach irritation for some people, but it does not eliminate the deeper bleeding risk that comes with regular aspirin use.
Side Effects and Bleeding Risk
The same clot-blocking property that makes aspirin useful for the heart also makes bleeding its most significant side effect. People on daily aspirin often notice they bruise more easily, get more nosebleeds, and bleed longer from minor cuts. These effects are common, occurring in more than 1 in 100 people taking low-dose aspirin.
More seriously, aspirin can cause ulcers in the stomach or intestines, especially with long-term use or higher doses. Mild indigestion is a frequent early sign. If indigestion persists even when you take aspirin with food, it may signal a developing ulcer. Blood in your stool, urine, or vomit, or coughing up blood, are warning signs that need immediate medical attention.
Who Should Not Take Aspirin
Children and teenagers should not take aspirin, particularly when they have a viral illness like the flu, chickenpox, or even a common cold. Aspirin use during these infections is linked to Reye’s syndrome, a rare but serious condition that causes swelling in the liver and brain. This applies to all aspirin products, not just Bayer specifically.
People with a history of stomach ulcers, recent gastrointestinal bleeding, or conditions that increase bleeding risk are also poor candidates for regular aspirin use. The same goes for anyone already taking other medications that thin the blood, since aspirin amplifies their effects. If you’re over 60 and haven’t had a heart attack or stroke, current guidelines suggest the risks of starting daily aspirin generally outweigh the benefits.