I give mine melatonin...as young as 1.5, and the dr says it's fine. It works great too. I think it's safer than benadryl or even tylenol. I only give it to them at night to help sleep. (It wouldn't work in the daytime anyway because it needs to be dark for the melatonin to work properly.) I really don't think melatonin is a drug though. It's like teething tablets, natural substances.
*hides behind the anon shield* lol