Charlie Sheen’s ex-wife, Brooke Mueller,  has entered a residential treatment facility, and it's not in Mexico, but rather, it’s in the United States, RadarOnline.com has exclusively learned.

Mueller had planned on going to Mexico to undergo treatment with the controversial drug Ibogaine to stop her cravings for illegal drugs. Ibogaine is classified as a hallucinogenic, and it’s illegal in the U.S.

Brooke Mueller lost her passport, and was unable to leave for rehab in Mexico, to take the controversial drug ibogaine, which isn't legal in the U.S., RadarOnline.com is exclusively reporting.

"Brooke made it to the gate with her doctor, who was going to accompany her, but the airline staff wouldn't let her board the plane. Brooke is going to get an emergency passport on Wednesday, and hopes to leave for Mexico as soon as she gets the new one," a source close to the situation tells us.

Dr. Drew Pinsky is "very concerned" about Brooke Mueller's plans to go to Mexico for an addiction program that isn't approved in the U.S., he told RadarOnline.com in an exclusive interview.

Mueller has suffered another setback in her ongoing battle with her addiction to drugs, specifically, methamphetamines, and she is going to be taking an extreme measure to attempt to get sober. Mueller plans to go to Mexico and enter a facility that will give her ibogaine, which is supposed to stop the cravings for drugs. Ibogaine isn't legal in the U.S.