Final answer:
Aspirin should not be used in children with viral infections due to the risk of developing Reye's syndrome, a severe condition that causes swelling of the brain and liver and can be fatal.
Step-by-step explanation:
A nurse should caution parents about the use of aspirin in children with viral infections due to the risk of Reye's syndrome, which can cause dangerous swelling of the brain and liver, possibly leading to neurological damage, coma, or death. Aspirin is an NSAID that should be avoided in children and teenagers during a viral infection to prevent this rare but serious condition. Since 1988, the FDA has required warnings about Reye's syndrome on all aspirin-containing products.