Her publicist, Craig Schneider, says in a statement that the 23-year-old actress remains in the hospital under doctor's orders.
Police say they removed Barton from her home on Wednesday afternoon for a medical problem. The department will not say what it was.
Schneider's statement also does not address Barton's condition.
The actress rose to fame as a star on Fox's teen drama "The O.C." She was arrested in December 2007 and later pleaded no contest to a drunken driving charge.