It's the latest setback in the 62-year-old's battle with cancer since she was first diagnosed in 2006.
In the midst of her hospitalization, Redmond O'Neal, Fawcett's son with Ryan O'Neal, was arrested Sunday on suspicion of bringing narcotics into a jail facility and was being held on $25,000 bail.
A deputy at a jail in Castaic, north of Los Angeles, was doing a security sweep of the jail's parking lot when he stopped the 24-year-old, who admitted he was carrying drugs and was apparently at the jail giving a ride to a friend, Los Angeles County Sheriff's Department spokesman Steve Whitmore told The Associated Press.
Redmond O'Neal was arrested along with his father last year at the actor's Malibu home on suspicion of having methamphetamine while on probation for a previous drug conviction. He has pleaded not guilty in that case.
Fawcett's Producer, Doctor Detail Her Condition
"On Farrah Fawcett's behalf, I can confirm that she recently checked into a Los Angeles hospital," Craig Nevius, the producer of an upcoming documentary about Fawcett's cancer battle, said in a statement to People magazine Sunday.
"And although it is usually against her nature to correct false or exaggerated stories that originate in tabloid-style reports by offering true information that they would not otherwise have to publish, Farrah is allowing this statement out of appreciation for her fans, who have offered their constant support throughout her fight, as well as out of concern for the countless other cancer patients who have written her over the last 2½ years in order to tell her that they are following her story in the hope that there is hope," Nevius said.
Nevius added that Fawcett "has hope" and is expected to return home in a few days.
Dr. Lawrence Piro, Fawcett's physician, who regularly consults with her doctors in Germany where she sought alternative cancer treatment, issued the following statement to reporters:
"There have been some photographs that have been widely published of Farrah Fawcett in a wheelchair. The reason she was in that wheelchair is because she had a small procedure while in Germany and left for the airport soon after. She could have stayed in Germany to recuperate for a day or two but she was really very anxious to come home."
As a result, Piro said, "she took a nine-hour flight right after that procedure. It turned out that the procedure caused a small amount of bleeding in one of the muscles of her abdomen, making a hematoma, which was quite painful. Actually, it was painful for her to walk, which is why she was in that wheelchair. And that pain, which was coming from the hematoma, had nothing directly to do with the cancer."
"She's able to walk. And she remains in good spirits with her usual sense of humor. She's been in great shape her whole life and has an incredible resolve and an incredible resilience," Piro said.
ABCNews.com's calls to Nevius were not immediately returned today.
Fawcett's Controversial Cancer Battle
Entertainment Web site Radaronline.com first reported her hospitalization Saturday and said Fawcett is in "bad shape."
The former "Charlie's Angel's" star was diagnosed with anal cancer in 2006. Although doctors declared her free of cancer in February 2007, a few months later they learned that the cancer had returned.
Fawcett's alternative approach to her cancer treatment has been surrounded by much controversy. After her initial diagnosis, Fawcett received traditional treatments in California.
According to People.com, Fawcett was "disheartened" by both the reoccurrence of the cancer and the treatment she was receiving in the United States, so she traveled to Germany's University Clinic in Frankfurt in search of an alternative course of treatment.
Some reports have said that she received experimental stem cell treatment while in Germany. But Nevius told ABCNews.com that while it's been widely reported, it has never been confirmed by Fawcett or sources close to her.
Nevius said that the actress' documentary that chronicles her battle with cancer, "A Wing and a Prayer," is slated to run on NBC later this year, although an air date has not yet been set.
Earlier, he told ABCNews.com that the footage was shot by Fawcett or her friends on a home video camera.
Last year, an employee at the UCLA Medical Center was disciplined for accessing Fawcett's medical records, a few weeks after the hospital announced that several employees had been fired for snooping in Britney Spears' records.
Fawcett's attorney told The Associated Press that an employee at the hospital reviewed the actress' medical records without authorization and then details about her treatment appeared in the tabloid the National Enquirer.
Fawcett first stepped into the spotlight playing Jill Munroe in the TV series "Charlie's Angels" in the 1970s. The series became a smash hit and Fawcett quickly became an iconic pin-up model for millions of men.
She later went on to win one of three Emmy Award nominations for her role as a battered wife in the acclaimed television movie "The Burning Bed."
The Associated Press and ABC News Research's Gerard Middleton contributed to this report.