Law enforcement sources tell us ... the Chicago Police Department raced to the Peninsula Hotel around 6:51 PM last night after receiving calls from the hotel after Kacey twittered several suicidal messages ... saying she had taken a bunch of pills and alcohol and was waiting to die.
We're told when cops got to the hotel, Kacey was sitting on her bed -- with prescription pill bottles, broken glass and alcohol all over her room.
Law enforcement sources tell us Jordan had cuts and scrapes to her wrists and arms ... but insisted the suicide messages were merely a publicity stunt.
While Kacey was talking to police, we're told the porn star grabbed a corkscrew bottle opener ... tried to run out of the room ... and attempted to cut herself.
Cops eventually subdued Kacey before she could further harm herself and took her to a nearby hospital for a mental evaluation.
We're told cops reported the incident as a non criminal suicide attempt.
No word on Jordan's condition.