Diatomaceous earth is an organic substance derived from the remains of fossilized shells. It can be used in the garden, or as a flour or powder in animals and humans for various health reasons. Diatomaceous earth is not usually considered toxic but can cause respiratory problems, if inhaled.
Diatomaceous earth is often applied in the garden. It can be used to prevent slugs and other soft-bodied creatures from attacking and eating plants by drying out their soft bodies. Touching the powdery mineral does not appear to cause any problems or side effects in humans.
The mineral is often powdered into a flour and used for various health reasons ranging from regulating bowel movements to increasing energy. The flour does not seem to cause any adverse side effects when taken internally.
Diatomaceous earth itself poses no problems. It is the silica that it is comprised of that can lead to breathing problems if it is inhaled over a long period of time.
Prolonged exposure to the silica dust in diatomaceous earth can cause breathing problems like silicosis and pneumoconiosis, which are degenerative respiratory diseases, according to an article in the Journal of Environmental and Occupational Medicine.
The powdered mineral is often used as an organic dewormer for pets without any adverse side effects. It can also be rubbed on to the dog or cat's coat to prevent an investation of lice and ticks. Aside from some dryness, diatomaceous earth appears to cause no problems to the animals.