I can say this much. At one time in 2012, I fed DE over the course of 6 weeks to my entire yard of dogs. I believe at that time there were 25-30. There were 2 particular dogs that I knew were wormy, so I thought this would be the perfect chance to see if it actually works. After giving a big tbsp of DE everyday in their food, at the end of those 6 weeks, those two particular dogs still had worms. At that point, I quit using the DE. As far as I was concerned, all the DE worming testimonials I read all went out the window.

That was my experience with DE. I'm sure it has some other benefits, but ridding the dog of worms isn't one of them IMO.