Detox potions, bentonite products, pills, etc all work via the principle of dilution. They do not convert THC metabolites into something that can't be detected, as they'd like you to believe. They do not remove THC metabolites from your body. Only time and fat-burning exercise can do that. The actions of these products can be duplicated for $$$ less by following this link:
http://boards.cannabis.com/drug-test...uidelines.html

Because they work by dilution, these internal remedies can fail if the concentration of THC metabolites is too high. Drinking fluids days before the test is of no help. Drinking a reasonable amount of fluids on the day of your test will dilute your urine, lowering the concentration of THC metabolites in the bladder. If you dilute too much it will spoil the test, triggering a retest or a fail. The aspects of dilution techniques other than drinking fluids are to make dilute urine appear to be less dilute. In other words, diluting just enough to test below the assays cutoff level. At high concentrations of THC metabolites, it is not possible to dilute enough without over-diluting.