Clay is a natural analgesic. It immediately reduces or eliminates pain when applied.
Most clays have a high alkaline pH. Acidity is the breeding ground for disease. Look for a clay pH between 9.0 and 10.0. Avoid acidic clays.
Calcium Bentonites exchanges a calcium molecule in the adsorption layer for a positive ion (a body baddie if you will) holding it captive to its magnetically dominant negative charge. Sodium Bentonite releases Sodium in its exchange layer.