Taking into consideration the results of this systematic review, the U.S. Preventative Services Task Force (USPSTF) has issued updated recommendations on aspirin use for primary prevention of cardiovascular disease and colorectal cancer. The USPSTF recommends initiating low-dose aspirin for the primary prevention of CVD and CRC in adults aged 50 to 59 years who have a 10% or greater 10-year CVD risk, are not at increased risk for bleeding, have a life expectancy of at least 10 years, and are willing to take low-dose aspirin daily for at least 10 years. The decision to initiate low-dose aspirin for the primary prevention of CVD and CRC in adults aged 60 to 69 years who have a 10% or greater 10-year CVD risk should be an individual one, considering the risks and benefits for the patient. The current evidence is insufficient to assess the balance of benefits and harms of initiating aspirin for the primary prevention of CVD and CRC in adults younger than 50 years and 70 years or older.