As a true non-believer in alternative medicine (mixing 2 natural medicine that should have been able to be mixed caused my dad to get leuchemia), my advice would be: "stay away from that s***".
There's only one preventive medicine for Anthrax and it doesn't work that great. It's administered by vaccine and it's effectiveness ration has never been tested on human (even if all servicemen and women who served in the Gulf War got it).
------------------
I'm the Wanderer without a clan... I bring justice without favorism. Though you may not agree with it, my judgement is final... and inconsequential