The main ingredient of aspirin, which is found in plant extracts such as willow bark, has been used for centuries as a pain reliever. In the late 1800s, a chemist synthesized a form of the compound, called acetylsalicylic acid, that was well tolerated in people and is found in aspirin tablets today.
In addition to relieving pain, the drug may have a number of other effects on the body. Here are five facts about aspirin:
Reduces the risk of heart attacks
Taking a low dose of aspirin daily may reduce the risk of heart attacks. That's because aspirin prevents cells called platelets from clumping together inside blood vessels. Platelet clumping is essential to repair wounds, but clots that are too large can block blood vessels and prevent blood flow, leading to a heart attack. This risk of blood clots is higher for people with atherosclerosis, or plaque buildup in the arteries.
The American Heart Association recommends daily, low-dose aspirin for people at high risk for heart attack, or who have survived a heart attack. However, people should speak with their doctor first about whether daily aspirin is right for them, AHA says.
Aspirin can have side effects, including an increased risk of gastrointestinal bleeding, that need to be weighed against the benefits of taking the drug.
Increases risk of tinnitus
Taking aspirin may increase the risk of tinnitus, or ringing in the ears. The risk is more likely among those taking high doses of aspirin (eight to 12 tablets a day), according to the University of California, Berkeley. It's thought that salicylic acid, a breakdown product of the main ingredient in aspirin, can damage the inner ear, UC Berkeley says.
Reduces risk of cancer
Studies have found a link between taking regular aspirin and a reduced risk of cancer, particularly colon cancer.
One study published in 2011 found that taking two aspirins a day lowered the rate of colon cancer by 63 percent among people at high risk for colon cancer. Another study published last year found that daily aspirin lowered the risk of death from cancer.
Aspirin blocks cyclooxygenase (COX) enzymes, which are produced naturally by the body, and are also produced by some precancerous tissues, according to the National Cancer Institute.
Despite growing evidence linking regular aspirin use with a reduced risk of cancer, the drug is not yet recommended as a way to prevent cancer.
Increases risk of Reye's syndrome
Children who take aspirin may be at an increased risk of Reye's syndrome, a rare condition characterized by sudden brain damage and liver problems. Symptoms can include prolonged vomiting, confusion and seizures
The condition has occurred in children who were given aspirin when recovering from the flu or chicken pox. Although aspirin is approved for use for children older than 2, it should never be given to kids who are recovering from the flu or chicken pox, according to the Mayo Clinic.
Problems in pregnancy
Aspirin and other non-steroidal anti-inflammatory (NAIDS) drugs, are not recommended during pregnancy, particularly in the last trimester. Because aspirin affects blood clotting, it may increase the risk of bleeding in the mother or fetus, according to the Mayo Clinic.
NSAIDS may also affect the ability of a blood vessel in the baby's heart to close, the Mayo Clinic says.
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Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.