I have done the parasite cleanse and didn't notice a big difference, but I still felt better after doing it. As for the liver flushing, I have done about 8. I have more energy, my chronic headaches are now just a minor, occasional thing, my gb attacks are few, far between, and much less severe. (I expect them to be gone someday, but the stones just aren't gone yet!) During a couple of my flushes, I woke up at night in pain- having a gb attack. I stopped it by drinking a little more epsom and a little more oo and gf juice. Since then, I use 3/4 c. of oo and have had no problems.
I would say any bad reactions or potential problems are greatly outweighed by the benefits.