I have used neem internally (powder form which I placed in capsules) with no ill effects. I noticed no affect on the parasites, though. Others have had positive results with relief from parasites with neem. Search here for posts. One thing for certain, I have never had such smooth, soft, clear skin as when I used neem. I am going to go back to it for that alone. Maybe your individual response to it in terms of parasites will be positive??