So you ingest something that enters your mouth, moves past your stomach and digestive acid and enzymes, makes it to the large and small intestine, does not get absorbed and neutralized by the liver and kidneys (designed to filter and neutralize foreign and harmful substances) makes it into the colon to only target parasites. Correct ?
So the mechanical action of fiber in your gut removes the parasites, based on what you are saying. A rough indigestible substance mechanically rubbing along a sensitive, porous and soft membrane.