[color=red]I have heard it is safe and can even rid his gut of parasites. How much and how often. I don't think he has many, but I am his third owner and just really don't want to over do it, with the de. Thank you and I will check back in a few days. Great site..so far.
Sue - I'm not an expert but I haven't seen credible evidence of DE working for internal treatments.
Externally it works by physically shredding the exoskeleton of mites. Once the exoskeleton is pierced the fleas/bugs etc lose moisture quickly through evaporation and die. This relies on the DE being dry, and the mites being in a dry environment (ie treating areas inside the home, brushing it through your dog's fur etc...)
Internally there is no reason to think that it would have the same physical effect on parasites, and if it did they wouldn't necessarily be killed because the intestines are a damp environment.
On the other hand, DE is basically just "dirt" - you shouldn't harm your animal by including some in their food, and I believe it is used in some dry food processing to stop insects getting into and damaging dry food stuffs.
Moderator, Treatment Free Beekeepers group on Facebook.
ask a veterinarian. as noted, DE works by shredding the chitin exoskeleton of arthropods. Its small and sharp. in mafia and prison movies people are often bumped off by grinding glass into a fine powder and adding small amounts to someone's food. the resulting internal bleeding is unstoppable. ask a vet for the dogs sake.