The actress, who is embarking on a career comeback after years of legal issues and substance abuse problems, was involved in a collision with an 18-wheeler trailer truck on the Pacific Coast Highway on Friday (08Jun12), TMZ.com reports.
Sources tell the website her black Porsche was left totalled after the crash.
An ambulance was called to the scene but the reports suggest Lohan made her own way to UCLA Medical Center, where she underwent medical tests.
As WENN goes to press, it is not known which hospital the actress has been admitted to or what her condition is.
There is also no word as to who was to blame for the collision, but Lohan sources tells HollyScoop.com the actress insists she wasn't at fault, telling friends the 18-wheeler cut her off on the freeway.
Sources tell the website that Lohan's assistant was a passenger in the car at the time of the crash. She was left bleeding and bruised.
The actress is currently shooting TV movie biopic Liz & Dick in L.A.