It is an FDA approved additive for livestock feed. It is volcanic ash. It cuts up the worms and kills them. It is acts like ground glass, but it doesn't hurt animals or humans, just parasites. You can get it at nurseries to put in the garden and control pests. Do not inhale it. Use googe to search for it and you will find dozens of places where you can order it. It works very well. I give it to both my dogs and I've taken it myself. It works.