The starlet wound up passing out in her SUV as gal pal Samantha Ronson, a celebrity DJ, drove them from an early morning Memorial Day bash at a Hollywood hot spot, the New York Post reported.
Photos show Lohan stumbling out of the trendy club Teddy's at the Roosevelt Hotel, then sprawled in the front passenger seat of her black GMC, her head lolling back, her mouth agape and her eyes firmly shut.
Lohan was so out of it, a witness said, that she wasn't even aware of the flashes from paparazzi snapping the photos.
Lohan's latest troubles began when she and Ronson sneaked in the back door of Teddy's at about 2 a.m. and partied for more than two hours, a witness said.
When the "Georgia Rule" star left, she stumbled through the back door and dropped her sunglasses and cigarettes. She bent to pick them up and collapsed, a witness said. A bouncer scooped her off the floor by her waist, and Ronson ran to get the car.
The bouncer placed Lohan, who had a cut on her left hand, into the passenger seat of the GMC — which had three plastic medallions from rehab treatment, each indicating 30 days of sobriety, hanging from the rearview mirror.
"She couldn't stand up anymore," one witness said. "She couldn't even move when she got in the car. Samantha was poking her. She didn't respond. She was totally passed out."
Soon after, Ronson stopped at a gas station on Beverly Boulevard and desperately tried to alert Lohan to paparazzi snapping her picture, but the actress didn't respond.
Ronson then drove aimlessly along the winding roads in the Hollywood Hills before heading back to Sunset Boulevard and then to a house where they both spent the night.
The pair's wild night came on the heels of Lohan's Saturday-morning crash, which happened after she and Ronson — the stepdaughter of Foreigner's Mick Jones — had a fight in the middle of Sunset Boulevard, with Lohan calling her a "f—-ing lesbian," according to the Post.
Lohan and two other people were in her 2005 Mercedes SL-65 when it crashed on Sunset Boulevard around 5:30 a.m., Sgt. Mike Foxen said. It appeared the actress was speeding, Lt. Mitch McCann said at a news conference.
Officers at the scene found a "usable amount" of a drug tentatively identified as cocaine, McCann said. He declined to say where the drug was found other than to say Lohan was not carrying it.
Lohan, who spent time at a rehabilitation center earlier this year, was driven in another car to a hospital for treatment of minor injuries, McCann said. The two other people in her car were not hurt.
Officers received a 911 call about the accident and arrested Lohan at the hospital for investigation of misdemeanor driving under the influence of alcohol or drugs, McCann said.
She was released from custody because she was admitted to the hospital, police said.
McCann declined to comment on Lohan's blood-alcohol level. He said the case will be presented to the district attorney's office, where the actress could face more charges, including felonies. Her tentative arraignment date is Aug. 24.
Lohan said in January that she had checked into a rehabilitation center for substance-abuse treatment. Her publicist confirmed in December that the actress was attending Alcoholics Anonymous meetings.
Lohan's latest movie, "Georgia Rule," is in theaters now. The actress' other screen credits include "Mean Girls," "Bobby," "A Prairie Home Companion" and "Freaky Friday."
The New York Post and the Associated Press contributed to this report.
Photo Essay: Lindsay Lohan