I would not be too aprehensive about using neem oil or neem products internally. I used neem leaf for some time in an helbal tea concotion for candida treatment and although it did not completely kill off the candida (I have a fairly severe infection) I can say that it did eliminate my symptoms while I was using it. As far as the essential oils (like neem oil) I would just make sure to only use a limited ammount at least at first. Essential oils are quite strong..