According to the American celebrity gossip website TMZ, the 25-year-old singer was taken ill at her home in the Hollywood hills on Tuesday (24 July) night.
It was reported the former Disney star was found unconscious and treated at the scene with Naloxone, an anti-overdose medicine.
She was then transferred to Cedars-Sinai Medical Center in Los Angeles where her family have been at her bedside.
Her spokesperson told the BBC: “Demi is awake and with her family who want to express thanks to everyone for the love, prayers and support.”
They added: “Some of the information being reported is incorrect and they respectfully ask for privacy.”
Stars including Ariana Grande, Ellen DeGeneres and Adam Lambert have shared their love and support for the star.
Demi - who has spoken openly about her struggles with alcohol and substance abuse - recently revealed she’d relapsed after six years of sober living in a heartbreaking ballad titled ‘Sober’.
“Momma, I’m so sorry I’m not sober anymore / Daddy, please forgive me for the drinks spilled on the floor,” she sings in the song’s chorus. “To the ones who never left me, we’ve been down this road before.”
Last month she topped the UK singles chart as a guest vocalist on the Clean Bandit single ‘Solo’.