Hello - Not to put down any other product out there, but I have never recommended using DE for internal parasite removal. Here's why: DE is actually ground fossilized sea urchins - it is microscopically razor sharp - it works on external fleas, ticks, spiders and the like. They crawl over the DE - it slices them - they dehydrate and die. I personally use it in my yard and around my barns and it works well - until it rains. When DE gets wet, it is no longer effective - even the bag instructions will tell you to reapply.
It will not work on soft worms - they are too "slick" for it to affect them. This is why it does not work internally on parasites. It looses its effectiveness when wet and the inside of the body is wet. I have known several cases of folks taking too much DE and their intestines stopping up.