According to magazine Us Weekly, the 20 year-old star has returned to the Las Encinas Hospital in Pasadena, California.
A source told the magazine: "She’s going to be in for a couple of weeks. She’s slipped into some of her old problems and is not doing so well. Everyone is supporting her."
Another source added: "Friends are concerned, but know that she’s strong and that she’s pulled through before and will this time as well."
The daughter of Ozzy and Sharon Osbourne was admitted to another drug treatment centre in April, 2004. She is struggling with an addiction to pain killers.