Have not noticed any difference when using advil. Make sure you are getting one without the added dyes as it could be that that is the real issue. My guideline is tylenol for fever and advil for pain. I have also been told by my doctor that both can be given since they are different drugs. When my kids were really sick as in the first couple days of things alternating them every 2 hours seemed to work the best because then they didn't go through the up and down swings as stuff wears off. After the initial days you can spread them out and give according to symptoms.