Bentonite is clay which is available in a supplement form. It is a natural clay formed by weathering of volcanic ash. It is distinguished from other clays by its extreme fineness, highly absorbent nature and curious property of swelling in water. It is an absorbent, containing the primary ingredient aluminium phyllosilicate. Other constituents in Bentonite include calcium, magnesium, and iron. Once in the body, Bentonite easily absorbs water. It remains in the digestive tract and is believed to bind and inactivate toxins and promote their excretion. It has been used effectively in detoxification, constipation, irritable bowel syndrome (IBS), and bloating & gas. Bentonite appeared to work best for people with constipation-predominant IBS. People taking the Bentonite clay experienced a significant improvement in abdominal discomfort and pain.
Bentonite, also referred to as Montmorillonite, is one of the most effective and powerful healing clays used to treat both internal and external maladies. It can be used externally as a clay poultice, mud pack or in the bath and, in skin care recipes. Internally it can be added to water or glazed upon food to help those with sensitive palates. It is very unusual in the fact that once it becomes hydrated, the electrical and molecular components of the clay rapidly change and produce an "electrical charge". Its highest power lies in the ability to absorb toxins, impurities, heavy metals and other internal contaminants. Bentonite clay's structure assists it in attracting and soaking up poisons on its exterior wall and then slowly draws them into the interior center of the clay where it is held in a sort of repository.
References:
Cathy Wong, About.Com. http://altmedicine.about.com/od/completeazindex/a/bentonite.htm
Botanical. Com. http://www.botanical.com/products/learn/bentonite.html