The 76-year-old director who faces being extradited to America from France after fleeing to the country in 1978 when he was convicted of unlawful sex with a minor was taken to an undisclosed hospital from his Swiss jail to get the necessary treatment.
His French lawyer Herve Temime said: "All I know is that he has been taken from prison for medical attention. I don't know where he is or when he will be returned to prison."
A spokesperson for Switzerland's Federal Office of Justice insisted the filmmaker is still under legal supervision, saying: "He is still in detention. If necessary he has all the medical care needed. It can be in prison or in hospital, in general."
Polanski was arrested in Switzerland last month and taken to jail, where he is awaiting to find out whether he will be extradited.
In 1977, Roman pleaded guilty to charges of having underage sex with 13-year-old Samantha Gailey, now known as Samantha Geimer.
He believed he would face a jail term of just 42 days, and claimed a judge had reneged on a plea bargain deal to reduce the charges from rape and serious sexual assault if he admitted under-age sex.
Polanski - director of a host of critically-acclaimed movies, including 1968's 'Rosemary's Baby' and 'Chinatown', released in 1974 - plied Samantha with alcohol and sedatives while photographing her for a magazine shoot at actor Jack Nicholson's Hollywood home. Nicholson was not present at the time of the incident.
Samantha - now a 45-year-old married mother - has previously asked prosecutors to drop the arrest warrant, while earlier this year lawyers acting for Polanski insisted the case should be dropped.
