But she is clearly still keeping hold of at least some of her vices: she was spotted holding a cigarette and what appeared to be a cup of coffee.
Lindsay's father Michael Lohan claims she suffers from multiple addictions
One friend told US magazine People: "We're all happy that she is where she is. Everyone's just been waiting [for something tragic to happen]. All of us thought there would be something soon."
After Lohan's arrest for driving under the influence last week, police said they found a substance tentatively identified as "a usable amount of cocaine" in connection with the accident.
The actress was with two other people in the vehicle when her ￡100,000 Mercedes convertible hit a curb and shrub on California's Sunset Boulevard.
She was photographed falling out of LA club Teddy's in what looked like a drunken daze the night after the crash before later checking into rehab.
In good news for the actress, producers of her upcoming film Poor Things have said they will work the filming schedule around her treatment.
This is Lohan's second stint in rehab - in January she was treated at Hollywood's Wonderland Center.