Babies should not take aspirin due to the well-established connection between aspirin and Reye syndrome, a potentially deadly condition, says WebMD. Over 90 percent of children who developed Reye syndrome had been treated with aspirin during a viral illness, such as flu or chickenpox, according to BabyCenter.
Aspirin is approved for children beyond age 2, but it should never be administered for symptoms typical of flu or chickenpox, states Mayo Clinic. Any person under 20 years of age should avoid products containing aspirin to ensure prevention of Reye Syndrome, recommends WebMD. Common products containing aspirin include Pepto-Bismol, Kaopectate and Alka-Seltzer. Aspirin on medicine labels may also be called acetyl salicylate, acetylsalicylic acid, salicylic acid, salicylate or subsalicylate.
Reye syndrome is rare, and its cause is unknown, as of 2015. It produces swelling of the brain, and it can lead to brain damage and liver damage. Most children recover if treated early, but if left untreated, Reye's can lead to death, warns Mayo Clinic.
Early signs of Reye syndrome are difficult to distinguish from flu symptoms. These include vomiting, lethargy, sleepiness, and strange or irritable behavior. Symptoms such as confusion, hyperventilation, violent outbursts, seizures or coma indicate that liver and brain damage are worsening, according to WebMD.