The actress was reportedly caught trying to sneak out of the Betty Ford Center in California to score herself some soda.
Lohan tried to get out of the famed rehab center, which has banned Coca-Cola, and over to the nearby Eisenhower Medical Center, which has it in vending machines.
But Lohan did not get far as her partner-in-crime's clothes got caught on a fence as they tried to get out, Radar Online reports.
'Lindsay and her co-conspirator had to give it up and flag down a volunteer, who was crossing the centre's grounds on a golf cart,' an insider told Radar.
'The pair was returned, decaffeinated, to their hall.'
Lohan has been seeking treatment at the rehab facility since she was jailed in September for violating her probation with a positive drug test.