I think people can take their own meanings from the lyrics, to me it speaks of abuse and trying to over come that abuse. When ever I listen to it all I can think of is a character from a book who was abused, molested and raped. And the scene where he's in the tub and scrubbing his skin raw, repeating over and over, "I'm dirty" "I'm poison," "Sick, sick, sick..." And it just makes me want to cry.