In an age of wonder drugs costing thousands of dollars a dose, pennies-apiece aspirin still has a place in your medicine chest, and not just as a fever or pain reducer. Its heart-health and colon-health benefits have moved it to a new level.


Aspirin is a blood thinner, and that makes it a lifesaver for many people at risk for heart attack or stroke, all through a very simple chain of events.

Aspirin, acetylsalicylic acid, is a compound that blocks the action of cyclooxygenases, or COX enzymes, that are found in every cell. The enzymes manufacture prostaglandins, hormones that control pain, fever and inflammation. By impeding prostaglandins, aspirin lowers fever, relieves acute pain such as headache and eases the soreness that accompanies inflammation.

COX enzymes also help produce thromboxane, which allows cells in the bloodstream called platelets to stick together, forming blood clots. Normally, platelets become “activated” when a blood vessel gets injured, and that’s a good thing—they get sticky and act like a bandage to plug a hole in a blood vessel wall, for instance. But when you have heart disease, platelets can get activated in the absence of any trauma. If they cling together and form a clot that blocks the coronary artery, which carries blood to your heart, a heart attack results. If a clot happens in the cerebral artery, the one that goes to your brain, it can bring on a stroke. Aspirin interferes with platelet activation, deterring platelets from becoming sticky and clotting.

Just how effective can aspirin be? People who take it daily are 25% less likely, on average, to have a heart attack or a stroke than people who don’t take it. That may not sound like an overwhelming number, but aspirin is as effective at preventing cardiovascular disease as statins, the commonly prescribed class of drug used to reduce cholesterol. It also reduces the risk for blood clots elsewhere in the body. For instance, it helps prevent clots in the legs, which can result from atherosclerosis in your peripheral arteries.

Because aspirin is an anti-inflammatory drug, it also may reduce ongoing damage from inflammation to the lining of your arteries. But aspirin isn’t for everyone…


Interfering with your body’s ability to form a blood clot is not always a good thing. You still need your platelets to stop bleeding both outside and inside your body, such as when a stomach ulcer bleeds or in case of a hemorrhagic stroke, which is caused by blood leaking in the brain. Both of these conditions (and other potential internal bleeding) are made worse by aspirin. If you have a health condition that carries a high bleeding risk, such as a blood-clotting disorder, the potential harm may be greater than the potential benefit.

In fact, aspirin itself can irritate the lining of the stomach and lead to bleeding as a side effect. If you have had previous bleeding in your gastrointestinal (GI) tract, the bleeding risk from aspirin is higher for you. This all means that going on an aspirin regimen for heart health has to be based on a careful evaluation by your doctor with all the pros and cons considered. You should also talk to your doctor if you’re already on aspirin therapy for heart health but never discussed these issues before starting it.

Another caution to be aware of: Some people have an aspirin sensitivity. Symptoms are similar to reactions from allergens and can range in degree from sneezing to anaphylactic shock. If mild, you may not realize it at first. Telltale signs: People with aspirin sensitivity often also have asthma and nasal polyps.


Assuming that you aren’t sensitive to aspirin and don’t have too much bleeding risk, the miracle drug’s second act involves preventing cancer. Low-dose aspirin guidelines released in 2016 by the US Preventive Services Task Force for the first time included colorectal cancer prevention as another benefit. There’s growing evidence that aspirin is associated with fewer deaths from this cancer, although how it helps to prevent colorectal cancer is not completely known, says Randall S. Stafford, MD, PhD, professor of medicine at the Stanford Prevention Research Center, Stanford School of Medicine, California.

There is some speculation that blood platelets also are involved in helping cancer spread from one part of the body to another. It looks like platelets cling to circulating clumps of cancer cells, creating a shell of sorts, which allows the cancer cells to circulate through the bloodstream without being detected by the immune system. Since aspirin keeps platelets from becoming sticky and adhering to one another or other structures in the body, it is able to stop the “platelet shielding,” as it is called. So together with the anti-inflammatory effects of aspirin, the impairment of platelets may be important in cancer prevention.

The same effect may also help prevent other cancers, especially cancers that arise in the glandular cells (often referred to as adenocarcinomas), including breast and prostate cancers.


Research is pushing ahead in other areas with more surprising and life-changing benefits. Example: There’s preliminary but promising evidence that aspirin may be helpful in slowing down cognitive decline from dementia.

There also is some data showing that aspirin may play a role in preventing diabetes or keeping it from getting worse. At the same time, a few studies suggest that people who have diabetes may be resistant to the effects of aspirin, so there is a concern that aspirin may not be as effective in people with diabetes as in those who don’t have it. But Dr. Stafford says that this data does not dissuade him from prescribing aspirin to people with diabetes who have other risk factors for cardiovascular disease such as high blood pressure or high cholesterol.


Don’t worry about the formulation. In most cases, aspirin doesn’t cause GI bleeding because it directly irritates your GI tract—the bleeding is caused by a systemic effect on COX. That means enteric-coated tablets don’t decrease the risk for GI bleeding.

Be cautious of blood-thinning supplements. Fish oil and the herb ginkgo biloba also affect blood clotting, increasing the risk for internal bleeding. If you’re taking aspirin, talk to your doctor about whether it’s safe to take those supplements.

Don’t take aspirin and another NSAID at the same time. Recent research shows that NSAIDs, such as ibuprofen (Advil) and naproxen (Aleve, Naprosyn), interfere with aspirin’s ability to affect COX. If you take another NSAID, take it four to six hours before or after taking aspirin.

Think twice about stopping aspirin before surgery. Surgeons often ask patients to stop taking aspirin seven to 10 days before surgery. But if you take aspirin for secondary prevention, the risk for a heart attack may outweigh the risk for additional bleeding during surgery. Ask your physician.

If you think you’re having a heart attack, call 911 immediately and take aspirin. Chew an uncoated full-strength (325 mg) aspirin right away. Taking aspirin once a day for the next month can reduce the risk for death by 23% and may significantly reduce damage to the heart.

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