I've done the cascara sagrada w/psyllium and senna and 2 forms of parasites cleaners.
I have to say that the cascara sadrada and senna worked okay for me to clean out the stuff that was loose and hanging out in my colon (just a little cramping), but the P&B shakes are far, far superior at moving stuff right on thru.
My advice would be to do some Epsom Salt to get things moving, then start with the P&B shakes. I make Epsom Salt 'pills' using empty gelatin caps I bought at the store and filling them up by hand with the Epsom Salt made for consumption. I pop a couple when I feel a little indigestion coming on, too. About 5-10 will get you moving. When I do a liver flush, 4 T are required (total) and that's about 60 total capsules - you can measure it. After those first 15, everything is moving south. You probably don't need 15 to get unconstipated, though.
I think everyone has parasites frankly. Some more than others because some people travel more and some people are less healthy and some people eat hi-risk (for parasites) diets. I personally love sushi and think that it's entirely possible that that and my travels around the world eating local cuisine caused me to get parasites. I also chew my nails, which is a good way to pick up eggs. And I garden and have a dog and am always sticking my hands in an aquarium...lots of ways to accumulate new 'friends'. I also think I've had them most of my life, but it took my gallbladder getting stopped up with parasites and stones (and the threat of having it surgically removed) that caused me to actually do something about them. So far I've seen pin worm, flukes, tapeworm, and 3 unidentifiables in addition to the candida coming out in my Liver Flushes and BMs after P&B shakes.
I believe that parasites are fairly benign in most people, just a part of life. But sometimes they move into a certain area or find conditions very conducive to breeding and flourishing and *poof* the person becomes very ill with some major problem. I think most all colon cancer is caused this way.