There have been many reports of parents getting confused and giving the wrong amount when they are alternating. For example, if the dose of Tylenol is 4cc and the Motrin dose is 10cc you could get confused and give 10cc of Tylenol instead. The younger the child, the bigger deal an overdose is. Overall, they've decided the risks outweigh the benefits. However, those here who are still being told to do it are probably known as intelligent conscientious parents by their pediatricians
and the doc feels that you won't make this mistake. Unfortunately not all parents are able to be trusted that way - even those who mean well can become confused if they aren't very careful doing this.
Laurie

Laurie