The veterinary pharmaceutical industry appears to be very keen that I expose my dog to toxins on a regular basis in order to prevent parasites taking hold.

I have heard that there are more natural alternatives, such as both feeding and dusting her coat with diatomaceous earth and/or garlic—especially when combined with periodic stool analysis.

  1. Is there any basis to these claims?
  2. Have the effectiveness of these (or any other) "natural" solutions been researched scientifically?
  3. Have the methods of action been identified?
  4. Have any harmful side-effects been noted?

3 Answers 3


Diatomaceous Earth claims say that it works on fleas/mites by microscopically abrading (cutting) their exoskeleton, essentially drying them out. Currently, there is no data on the amount of time is necessary for an organism to be exposed to DE before it has effectively "killed" the organism. However, your dog shouldn't be exposed to DE for more than 12 hours and there are some risks involved with using DE:

  • DE is very drying, and should be washed out within 12 hours.
  • In handling of DE, precautions state to use a mask. Keeping it away from your pet's mouth, eyes, ears, etc. are very important.
  • Use only food grade DE (much finer powder) as other forms of DE are poisonous.

Some sites say that ingesting DE also works to deworm a pet. My issue with this is that DE is effective in a dry state; your pet's stomach and intestinal tract are full of water rendering the DE useless. Additionally, ingesting DE may be increasing the risk of intestinal related issues in your pet (i.e. constipation, etc.).

Sources: http://vetmedicine.about.com/od/parasites/a/Diatomaceous-Earth-For-Flea-Control.htm http://www.the-chicken-chick.com/2012/05/diatomaceous-earth-de-benefitrisk.html


So called "natural" remedies are not necessarily: more effective; or with less side effects.

Diatomaceous earth and garlic, to whatever degree they do work, would have much worse effects on your dog than on the parasites in it. Dogs do not have cytochromes in their guts like we do, so garlic is not good for them (as it is for us) but actually bad for them. Diatomaceous earth is just tiny silica skeletons it will hurt your dogs cells just as readily as those of the parasites.

Almost anything that will kill parasites will have some unpleasant side effects on the host animal. I'd actually expect much less side effects, and more effectiveness, from those pharmaceuticals (which have been developed using science).


Diatomaceous earth is a sediment composed of diatoms, which are hard-shelled algae. On a microscopic level, it's incredibly sharp, which makes it useful for piercing the exoskeletons of small pests. It then kills them by drying them out.

  1. There is a basis that diatomaceous earth is useful. I would not recommend dusting your dog's coat with diatomaceous earth, as it is prone to get into the eyes/nostrils. It is a mild irritant and abrasive, so it can cause irritation for your dog. However, only food-grade diatomaceous earth can be consumed by your pet. It does have some dietary benefits and can help with internal parasites.

  2. As to the scientific efficacy of diatomaceous earth as a natural pesticide, I have not found many studies supporting the case. However, pest-control websites seem to swear by it.

  3. Methods typically involve spreading food-grade diatomaceous earth in the environment that your pet inhabits. This can be your garden, home, etc.

  4. Again, only food-grade diatomaceous earth is safe for humans and pets. The negatives are that it's a mild abrasive/irritant, so wear a mask and gloves and you'll be fine.


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