Doc Sutter has a forum on CZ and he has a Liver Flush he recommends. I have done it and it was not too bad. I have not done any other liver flush. The thought of it turned me off.
Although, to be fair, I do not have pain in my liver. I know I have a sluggish liver, due to years of alcohol consumption (over 2 years ago, I stopped that), as well as drugs(very long time since I have done that) and lots of sugar...LOL that is recent!...
Go and check it out. It is not as intense as Clark's or whomever elses out there.