Because all teething mixture (babyrex, bonababe, piccan etc) all contain paracetamol. And using as prophylaxis for teething is wrong as prolong use or overdose could lead to PCM toxicity (liver damage). Also, we can't tell when these babies will actually teeth. My 7mo baby hasn't grown any tooth, so imagine I have been given her med for it from 3mo. Give only when needed (having fever)