It sounds like it works somewhat like metamucil.
c/p
The non-swelling calcium bentonite is sold within the alternative health market for its purported cleansing properties. It is usually combined with water and ingested, often as part of a detox diet, in a practice known as geophagy. It is claimed that the microscopic structure of the bentonite draws impurities into it from the digestive system, which are then excreted along with the bentonite; no scientific studies exist to support these claims. There are claims that native tribes in South America, Africa and Australia have long used bentonite clay for this purpose.

Maybe FBR will be able to answer.