Brooke Mueller's Unusual Rehab Treatment

Sources connected to Brooke tell TMZ ... Brooke is going to a treatment facility in Cancun that specializes in prescribing a drug that is not legal in the U.S. It's called Ibogaine, a substance extracted from an iboga plant. Some studies show it interrupts addictions to alcohol, cocaine, methadone and heroin.

Brooke is saying the program is seven days and it's "extreme," but she's confident it will "rewire" her brain to break her addictions.