I have not taken it on a long term basis because it constipates me so badly. And because it only seems to work on the big ones in the digestive system. Some parasites are microscopic and get in the blood. Others drill holes in all the tissues and travel throughout the body. The jaw is a great nesting place for pinworm, for example. The doctor told me that EVERYBODY has strongyloids, which are (apparently) something like teensy weeensy pinworms.
Two things, do not neglect systemic cleansing of your blood.
And flush, flush, flush your liver and gall bladder. Iodine will clean up the blood. Flushing the liver and gall bladder will help you eliminate the nests of eggs that keep hatching out when you stop taking the DE.