I have taken a few but the one I'm using now is fabulous as it has ox bile in it which helps keeps you regular while assisting the liver to dump toxins. I was constipated for about 30 years until I starting taking it.
Its called "Digestplex" by Nutriplex formulas. Its a whole food supplement. I get it from my nutritionist so I'm not sure if its available to non-professionals, but its worth looking into.