Here's what DE is: Diatomaceous earth consists of fossilized remains of diatoms, a type of hard-shelled algae. It is used as a filtration aid, as a mild abrasive, as a mechanical insecticide, as an absorbent for liquids, as cat litter, as an activator in blood clotting studies, and as a component of dynamite. As it is also heat-resistant, it can be used as a thermal insulator. (That's from Wikipedia). According to MM's website, WormGuard Plus is: The main wormer in WormGaurd is a more concentrated form of FDA aopproved Food Grade Diatomaceous Earth which consist of tiny phytoplankton's mainly composed of amorphous hydrated silicates, of less that 1%. This is packaged especially for poultry (with whole flax-does not need refrigeration). So between reading their catalog and what it says on their website I'd say WormGuard Plus is DE with other things (flax seed, lactic acid bacterias) added.
