I found this interesting-- I know some of these plants listed are toxic and kill animals too though- Lupine, for example. They say that.

Some interesting notes that could also affect humans:

It is crucial to choose the right time to carry out deworming treatments. At a certain stage of their development inside the animal, some parasites embed themselves in the mucous membranes and enter hypobiosis (e.g. Ostertagia). They are largely inactive at this stage and relatively harmless to the host. Deworming treatments have little or no effect when performed at this time.

MOON PHASES:
According to a traditional French practice, deworming treatments are performed preferably when there is a new moon. The worms are more active at this time and therefore easier to dislodge. On the other hand, Rudolf Steiner, the father of biodynamic agriculture, recommends performing deworming treatments during a full moon.



http://goatconnection.com/articles/publish/article_55.shtml