Is it safe to bathe in pine sol?

This might be a dumb question.. But I just need like a website I can go to to prove that females shouldn't put pine sol in their bath water.. This is why I ask.. The other day I was about to take a bath and my Gma said, "put a little pine sol in your water, because that's what I do to really get clean." I want to tell my Gma that that's unsafe but she won't believe me unless I show her something stating that it is so...