Aspirin is the most widely used medicine in the world—and it’s not just because it’s an effective pain reliever. If you’re at high risk of a heart-related problem, like a heart attack or stroke, your doctor may have told you to take a low dose of aspirin every day for heart health. That’s because aspirin has been shown to reduce the risk of heart attack and stroke, and even a low dose can accomplish this important feat while minimizing possible side effects. How Aspirin Works When you get a cut, special clotting cells in your blood, called platelets, will migrate to the site of the injury and clump together, forming a plug (which becomes a scab) that stops the bleeding and initiates wound healing. You might be familiar with this process when it happens externally, but this also occurs on the inside of our bodies. And while these blood clots are helpful for a skinned knee, they can cause serious problems in specific areas of your body. Over the years, especially if those years are filled with fast food and sitting at a desk all day, plaques build up along the lining of your blood vessels. These plaques are more likely to form if you have high blood pressure, high blood sugar levels, high cholesterol, or if you smoke. Sometimes, these plaques will rupture, and platelets will rush to the scene to clot the blood. When enough platelets build up, they can create blood clots that block blood flow. This means that your blood can’t deliver oxygen to your tissues. When your heart can’t get oxygen, you may experience a heart attack, and when your brain can’t get oxygen, you may experience a stroke. Here’s where aspirin comes in: it prevents the platelets from clumping together—then, they can’t form blood clots and won’t end up blocking blood flow to your heart and brain, thus preventing heart attacks and strokes. Like other nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil) and naproxen (Aleve), aspirin blocks enzymes in the body called cyclooxygenases (COX). COX enzymes help produce chemicals called prostaglandins, and some prostaglandins cause blood platelets to clump together, or clot. By blocking the production of prostaglandins, aspirin stops the blood-clotting process and allows oxygen-filled blood to reach the places it needs to go. Side Effects to Consider It’s important to understand that aspirin, like most medications, has some side effects. Some prostaglandins protect the lining of the healthy stomach, so when aspirin stops prostaglandin production, the stomach is left without protection. As a result, aspirin can cause stomach pain, but this can be avoided or lessened by taking aspirin with food. Aspirin may also cause gastrointestinal bleeding that can be serious. The risk of bleeding increases if you’re older than 60 years old, have had previous stomach ulcers or bleeding problems, take a blood thinner or steroid drug, or take more than the appropriate dose. And people who consume three or more alcoholic drinks every day should avoid taking aspirin, as this can greatly increase the risk of bleeding. These side effects are the reason that doctors recommend a low dose of aspirin daily for heart attack and stroke prevention. Studies have shown that a low dose of about 80 milligrams is just as effective at preventing heart attack or stroke as the typical 325 milligram dose used for pain relief—and with a lower dose comes a lower risk of side effects. If you’re thinking about starting a daily regimen of low dose aspirin for heart health, talk to your doctor first. While daily aspirin use can keep your heart healthy, it’s not safe or beneficial for everyone, and it can cause more harm than good in some cases.