Brooke Mueller has been rushed to hospital after a suspected overdose.
The former wife of Charlie Sheen - who has twins Bob and Max, three, with the Anger Management star - was reportedly taken from her home in Los Angeles to a nearby hospital.
According to gossip website TMZ, Mueller is now "conscious and responsive" but those around her are "deeply concerned" as they claim she has been taking drugs for the past few weeks.
In June, Sheen urged Mueller to check herself into rehab after he became concerned about her.
Mueller - who has struggled with substance abuse issues in the past - reportedly appeared "out of it" when she paid a visit to her ex-husband.
A source close to Mueller said at the time, she "partied for four days straight ... and ultimately fell off the wagon".
The insider added: "Brooke's family is hoping that she finally understands the consequences of her actions. That is, she risks losing all of her rights to the children if she doesn't get clean - once and for all."
Mueller, 34, is said to have missed Mother's Day with her twins on May 13 while partying, with her mother Moira Fiore looking after the kids.
However, Mueller's representative Steve Honig claims her recent hospitalisation was planned.
He said: "As part of her ongoing treatment and as planned, she voluntarily checked herself into a rehab facility several weeks ago."