After attempting a run for the border to get her hands on ibogaine, a substance that allegedly cures cravings for drugs, Brooke Mueller is giving rehab yet another try in a more conventional way. Last week, we reported her attempts to go to Mexico, where ibogaine is legal to treat addicts, in a last-ditch effort to cure her addiction. Mueller has attempted rehab more than 15 times, her last attempt being a 45-day outpatient program, which led her to use within days of being released. However, Radaronline.com reports that two attempts to head south failed. First, Mueller fought with a flight attendant who wouldn't let her use the restroom as the plane took off. Then last Wednesday, Mueller, accompanied by her doctor, forgot her passport and was turned away at the gate. A source tells Radar, "She was convinced that was a sign to not go to Mexico. Brooke was aware that Ibogaine is a very dangerous drug to take, and could potentially do more harm than good for her." So late last week, Mueller entered an inpatient facility in the United States. "This was a very big step for Brooke to take," the source says. "Brooke has resisted entering a residential facility because she didn't want to be away from her sons. Brooke did complete several outpatient programs in the past six months, but she would quickly relapse. Brooke finally realized she had to check in for intense treatment." No word on where her twin sons with Charlie Sheen will stay while Mueller takes care of herself.