How many days of high fever is safe for children?

Think differently: Generally it's not the temperature that harms the child it's the cause. It doesn't hurt to have a doctor examine any child with a fever, even one day's worth. A child can't tell you what's wrong you have to look yourself. Better to go to the doctor and be told, don't worry it's just a cold, than to blow off the temp and find out later it was something serious.

5 days: Any high fever lasting 5 days or more needs to be evaluated.

Fever- see doc?: When to see a doctor when your child has a fever? Depends on the age and how the child is doing: http://www.parenting.com/health-guide/fever/when-call-doctor