HARRIS GREEN Food Grade Diatomaceous Earth is a natural product composed of ground freshwater diatomaceous earth. It is a nutritional supplement recommended to mix in animal feed. Food Grade quality allows the product to be mixed in animal feed for horses, chickens, dogs, cats, cattle and many other animals. OMRI Listed as organic under the USDA’s National Organic Program. Includes a powder duster for easy application and to reach into cracks and crevices.