The 49-year-old star has become increasingly frail recently was picked up by an ambulance following a 911 call around 10.45pm last night.
A spokesperson for the actress said: “Because of the stresses in her life right now, Demi has chosen to seek professional assistance to treat her exhaustion and improve her overall health.
“She looks forward to getting well and is grateful for the support of her family and friends.”
Moore split from her 33-year-old husband, Ashton Kutcher, in November after he was caught cheating with admin assistant Sarah Leal, 22, on the night of their wedding anniversary.
But it is rumoured that the Ghost star is being treated for substance abuse.
Moore was with a female friend when she began shaking, TMZ reported, and an ambulance was called.
The mother of three has lost weight since the split and her frail appearance has shocked fans.
Earlier this month she spoke in an interview with US Harper’s Bazaar about her fears that she was “not loveable”.
She said: “What scares me is that I’m going to ultimately find out at the end of my life that I’m really not loveable, that I’m not worthy of being loved. That there’s something fundamentally wrong with me.”
Moore’s friend, Eva Longoria, has tweeted her support for the star: “Sending my love and support to one of the most beautiful people i know @mrskutcher”.
Reports say that Moore has also dropped out of her upcoming role as feminist Gloria Steinem in a biopic by Rob Epstein about porn star Linda Lovelace.