Diatomaceous earth works in two ways. It 1. Is a drying agent, so it dries out exoskeletons of bugs such as lice! It absorbs so much liquid that it takes their waxy coatings which keep them alive away. Unfortunately, the stomach is a moist environment so it cannot suck the moisture from the worms and kill them.
The second way is that it is very glass-like in texture - it slices and dices worms in the stomach!
DE has no anti-parasitic properties, it just physically kills them.
HOWEVER, you need an incredibly large amount of it to have any effect whatsoever on the internal worms. The goal is to kill them, not give every 1 out of 500 of them a paper cut.
I believe the recommended dosage was about 1/4 cup a day!!!
Even then, I have never heard of true success in using it!
The only benefit that I’ve heard of is that it dries fecal matter out quicker which can sometimes kill larvae in the poop, as they need moisture to survive.