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Pros and Cons of Aspirin

In this post, what we discuss is specifically related to aspirin. However, same descriptions can be similarly applied to other NASAIDs (Nonsteroidal anti-inflammatories) such as ibuprofen, naproxen, or indomethacin. Long-term use of aspirin has both positive and negative effects. In the following, we list the pros and cons of using it. If you choose to use aspirin (or NASAIDs in general) for their benefits as Dr. Andrew Weil[13] does, consult with your doctor first. Don't take aspirin if you have ever had ulcers, liver or kidney disease, bleeding disorders, or bleeding in the stomach or intestines.


  • Sir John Vane, who won the 1982 Nobel Prize for medicine for his elucidation of the therapeutic effect of aspirin. He showed that aspirin and related anti-inflammatory drugs worked by inhibiting enzymes that convert arachidonic acid to pro-inflammatory hormones.
  • By influencing on enzymes that mediate inflammation, aspirin can reduce cancer risks[9] because those hormones also increase cell proliferation and the risk of malignant transformation. The best evidence here is for prevention of colorectal cancer[10,18,22]. Aspirin may also reduce the risk of cancer of esophagus and some other organs.
  • A randomized controlled study[10] has suggested that aspirin might reduce risk of cancer with distant metastasis.
  • NASAIDs may lower the risk of developing noncancerous polyps in the colon. However, it is not clear if taking NSAIDs can result in a lower risk for cancerous polyps or not.
  • Taking one aspirin a week may help protect against breast cancer.
  • Researchers are looking at whether one 325-milligram aspirin tablet, taken every other day, can help protect against cataract formation or slow the progression of cataracts. However, it's too early for doctors to begin recommending aspirin to their patients for cataract prevention.
  • Some studies have suggested a link between a reduced risk for Alzheimer's disease and the commonly used painkillers NSAIDs. The link between NSAIDs and a lower Alzheimer's risk was made when researchers observed that people who take NSAIDs for chronic conditions such as arthritis or other immune disorders have lower rates of Alzheimer's disease. More studies are needed to confirm or refute this finding.
    • Doctors sometimes prescribe aspirinwarfarin, or other drugs to prevent clots from forming in small blood vessels for vascular dementia patients.
  • If your doctor recommends it, taking a daily aspirin tablet can help lower your risk of having a heart attack by helping to prevent the formation of blood clots. This is thought to be due to its action on platelets. It makes them less sticky, less likely to clump together and initiate blood clots, which are the immediate causes of coronary occlusions.
  • Both AGEs (or Advanced Glycation End products) and cross-linked proteins can initiate inflammatory and autoimmune responses and stimulate cells to proliferate, all of which can lead to further damage. Aspirin is believed to be able to undo the pathological bonds created in proteins by AGEs.
  • Daily aspirin use is associated with a modest decrease in mortality from cancer, particularly for malignancies of the gastrointestinal tract, a large retrospective study confirmed[7].
  • In the May 5, 2017 issue of Science Immunology, scientists reported that:
    • In extensive preclinical tests, a promising T cell therapy more successfully boosted immunity against melanoma when common antiplatelet drugs such as aspirin were added.[21]


    • Seniors who take aspirin daily are twice as likely to have late stage macular degeneration than people who never take the pain reliever, according to a new study[5].
    • A study reveals that drug toxicity - in particular due to acetaminophen - has replaced viral hepatitis as the most single frequent cause of acute liver failure (ALF) in a densely populated urban area of Germany[17].
    • Taking a regular dose of aspirin is more likely to harm than benefit healthy people with no history of cardiovascular diseases given the risk of internal bleeding that arises from such routine use of the drug, according to a UK-led study published online in the Archives of Internal Medicine[6]
      • Also, taking warfaringinkgo biloba (an herbal supplement), and vitamin E together can increase the risk for internal bleeding.
    • Aspirin's blood-thinning effects can slightly elevate the risk of hemorrhagic strokes (bleeding inside the brain), which are rare events by themselves.
    • Common side effects include nausea, vomiting, ringing in the ears, and decreased hearing. Each of these is reversible within a few hours if the drug dosage is decreased.
    • Long-term use of Aspirin can interfere with the stomach's natural ability to protect itself from stomach acid and other digestive juices. It can irritate the stomach and intestinal lining, which promotes the development of ulcers. Sometimes it can cause bleeding in the stomach and intestines.
      • As a matter of fact, regular use of NSAIDs is the second major cause for ulcers[16].
    • If you have kidney disease, you should avoid aspirin because it could cause kidney problems.
    • During pregnancy, should avoid aspirin because it can be harmful to a developing fetus. It's especially important not to use aspirin during the last 3 months of pregnancy, because it could cause excessive bleeding during delivery.
    • You don't want to give aspirin to people with ordinary fevers. Elevation of body temperature is an immune response that favors the efficiency of cells that fight germs; lowering it artificially makes it harder for those cells that fight germs[8].
    • Aspirin can initiate asthma attacks in some susceptible individuals.[20]
    • While the cause and cure remain unknown, research has established a link between Reye's Syndrome and the use of aspirin and other salicylate containing medications, over the counter products, and topical use products.
    • Taking aspirin will increase nutritional needs for iron, vitamin C, and folic acid.
    • Some people develop nasal polyps or wheezing with aspirin; if you are one of those people, these drugs are not for you.
    • Regular use of aspirin, NSAIDs, or acetaminophen increases the risk of hearing loss in men, and the impact is larger on younger individuals[15].


    Let's conclude this article with Dr. Agus' statements[12]:
    Does the balance tip the scales in favor of your taking a daily baby aspirin? That's a question for you to answer with your doctor.  While the study[9-11] didn't find any difference in the results between men and women, the age of the patients affected the findings significantly; older patients benefited a lot more from daily aspirin than younger ones, and the ideal candidates for a daily dose of aspirin are probably those nearing their fifties.

    1. American Medical Association--Complete Guide to Prevention and Wellness
    2. "Healthy Aging" by Andrew Weil, M.D.
    3. National Reye's Syndrome Foundation
    4. "The Arthritis Helpbook (6th ed.)" by Kate Lorig, R.N., Dr.P.H., and James F. Fries, M.D.
    5. Study: Daily Aspirin Tied to Risk of Vision Loss
    6. Routine Aspirin More Likely To Harm Than Benefit Healthy People
    7. Aspirin a Day Tied to Lower Cancer Mortality
    8. Are You Fever Phobic?
    9. Short-term effects of daily aspirin on cancer incidence, mortality, and non-vascular death: analysis of the time course of risks and benefits in 51 randomised controlled trials
    10. Are we ready to recommend aspirin for cancer prevention?
    11. Effects of regular aspirin on long-term cancer incidence and metastasis: a systematic comparison of evidence from observational studies versus randomised trials
    12. The End of Illness by David B. Agus, MD
    13. Does a Daily Aspirin Really Help?
      • Dr. Weil currently takes 162 milligrams, two low-dose tablets or half a regular tablet.
    14. Aspirin's Mostly Unrecognized Connection to Serious Medical Problems
    15. Analgesic use and the risk of hearing loss in men.
    16. Aspirin and NSAIDS (American College of Gastroenterology)
    17. Acute liver failure in a metropolitan area in Germany: a retrospective study (2002 - 2008)
    18. Gene mutation key to aspirin’s benefit in people with colorectal cancer
      • A new Harvard-based study suggests why taking aspirin helps some—but not all—people with colorectal cancer.
    19. An Aspirin a Day? Only If You Have Had a Heart Attack
      • If you never have had any cardiovascular problems, the Food and Drug Administration (FDA) says you should not take aspirin to avoid a heart attack or stroke.
    20. Aspirin Induced Asthma
    21. Platelets suppress T cell immunity against cancer
      • The researchers noted that antiplatelet drugs (i.e., aspirin and clopidogrel) by themselves were not successful in combating melanoma in their experiments.  However,  mice with normal platelets that were given melanoma and then adoptive T cell therapy survived longer and relapsed less when aspirin and clopidogrel, two antiplatelet drugs, were added
    22. Systems Pharmacogenomics Finds RUNX1 Is an Aspirin-Responsive Transcription Factor Linked to Cardiovascular Disease and Colon Cancer
      • Aspirin's ability to inhibit COX-1 may not be required for its effect on platelet function because salicylate has a ~ 20-fold lower potency for inhibiting COX-1 (Riendeau et al., 1997). Therefore in addition to the well-known effects of aspirin on platelet COX-1, authors' findings identify an effect of aspirin (or its metabolite salicylate) on RUNX1 and downstream gene expression.
    23. Gut Microbe-Dependent TMAO from Dietary Choline Found to Be Prothrombotic in Humans
      • It appears that the platelet hyperresponsiveness mediated by elevated TMAO can be attenuated by low-dose aspirin.