I dont know for sure if castor oil kills them outright, perhaps the small ones. Castor oil help undo the damage the parasites are doing to your body. parasites tells your immune system to stand down. There is a place in your stomach near the belly button that contain the major part of our immune system. Placing castor oil pack on this is supposed to jumpstart it. anyway i hope others will do more research and share..
As a maintenance its good to apply a small amount each day for an hr or so and wipe off with baking soda.. it can be hard on skin... baking soda neutralize the effect on the skin.