Supposely DE is sharp enough to cut the exoskeletons of mites and lice, killing them. Some people insist it is a great wormer however when DE gets wet internally its clumping action may not allow it to exert this sharp edge ability. There is doubt surrounding all of its quality. Some say it does help put on a healthy shell on an egg though. Use it with caution, and ALWAYS wear a mask when using it, it will cut your lungs.