Aspirin is one of the oldest nonopioid oral analgesics. Aspirin can cause gastric irritation and affects platelet function, thus increasing the risk of bleeding. Aspirin has also been linked to the development of Reye’s syndrome in children, a life threatening condition that causes acute encephalopathy and fatty infiltration of the liver and other organs.

Because of this association, aspirin should not be given to children under age 12 who have viral illnesses, such as upper respiratory infections or influenza. Since 2003, the U.S. Food and Drug Administration (FDA) has required that all aspirin products contain a warning label describing the potential for the development of Reye’s syndrome.