Sources told TMZ Demi was transported by ambulance from a home in the Hollywood Hills just before noon Tuesday, and is currently being treated.
She was found unconscious when paramedics got to her home where the overdose is believed to have taken place.
Demi has fought substance abuse for years - at one point she lived in a sober living home after getting released from a treatment center. She had been 6 years sober from alcohol, cocaine and Oxycontin.
