Aspirin can pose dangers to children or teens. Do not give it to children or teens with fevers, chicken pox, or symptoms of the flu because this puts them at risk for Reye's syndrome, a life-threatening condition that causes the brain and liver to swell. Emergency medical treatment is needed for symptoms of Reye's, such as seizures and delirium. The National Reye's Syndrome Foundation also cautions about the use of aspirin by pregnant or breastfeeding mothers because of possible risks to their babies. If you are pregnant, breastfeeding, or plan to be, discuss the risks and benefits of aspirin use with your doctor.