Taylor Momsen, who plays Jenny Humphrey on the CW hit "Gossip Girl," was being treated for a "severe, potentially life-threatening throat infection," Us Magazine reported.
"I have been treating Miss Taylor Momsen for the last few days," Momsen's doctor, Shawn Nasseri, told Us Magazine. "She has been hospitalized for a severe, potentially life-threatening throat infection since Sunday."
The 15-year-old was released from L.A.'s Cedars-Sinai Medical Center Wednesday afternoon, according to the magazine.
A source told Us Magazine the actress "woke up with a sore throat," while in L.A. to take a school exam.
"She thought it was just a common cold, but was advised to see an ear, nose & throat specialist before getting on a plane back to New York," the source said.
Momsen's mother flew from New York to L.A. to be with her, and the pair are expected to fly back to the East Coast this week, the magazine reported.