Aspirin (low-dose)

Low-dose aspirin (usually 75 to 100 mg a day) permanently blocks an enzyme (COX-1) in your platelets. That cuts their production of thromboxane A2 and makes them less likely to clump. It is approved for secondary prevention of heart attack and ischemic stroke. There, the benefit clearly outweighs the bleeding risk. But for healthy older adults, the picture is different. The ASPREE trial found no cardiovascular benefit. It found more major bleeding. And it found an early signal of higher all-cause death (largely cancer-driven, and softened in the extended ASPREE-XT follow-up). So current guidelines discourage routine use for primary prevention. The USPSTF (2022) recommends an individualized decision in adults 40 to 59 with at least 10% 10-year heart-disease risk. And it recommends against starting it in adults 60 and older. Its cancer-prevention signals remain experimental.

Last reviewed: June 22, 2026

This definition is educational and is not medical advice, a diagnosis, or treatment. Talk to a doctor about any health decisions. Read our full medical disclaimer