Profits acquired through making people sick, such as
Big Biz's hooking them on tobacco/alcohol/drugs/gambling, or a
doctor's using methods and/or treatments that he knows will probably just either make his patients feel even worse or give them maladies/injuries that they didn't even have before.
It's difficult enough to prove in court that someone knew
beforehand that his products or services would harm his customers, but then if he is eventually found
guilty and ordered to
finance a settlement, it's even harder to get him to part with any of his ill-gotten income.