While I would have to disagree with the term "dirty blood," I do think that the food you eat can sometimes be the root of an acne problem. Specifically, I am talking about a food allergy. I have had cystic acne for the past 4 years. The only time it cleared up was when I limited my dairy intake (and obviously supplemented my diet with some calcium tablets). Getting rid of dairy in my diet was hard, and I gave it up, so the acne returned. I am going to try eliminating dairy again and see if I find the same effect.