Robert Downey Jr's 'nightmare' as son goes to rehab, seeking drug treatment

ROBERT Downey Jr's eldest son has checked into a rehab facility.

The actor's 20-year-old son, Indio Falconer Downey, has been admitted to a rehabilitation facility according to his mother, actress and singer Deborah Falconer.

Falconer, who left Downey Jr in 2001 following his repeated trips to rehab, confirmed her son's admittance to the unnamed institution but stressed that Indio is not an addict.

"He was not addicted. He was taking one pill a day," she told the National Enquirer.

She added that Indio is receiving "holistic, natural and orthomolecular. We are hoping to do it the homeopathic way rather than with medications. He's being treated with vitamin supplements and organic foods".

Indio Downey plays in a rock band, and has recently played at top LA night spot The Viper Rooms.

A friend close to the family opened up on how hard this has been for his 48-year-old father, and what a shock it was.

"This is a nightmare for Robert because his boy has never been in trouble before. He's praying for Indio's recovery," the source said.

The Iron Man star has had a well-documented history with drugs and rehab, and was arrested in 1996 for possession of heroin, cocaine and an unloaded handgun.

He even served a one-year prison sentence in 1999 after missing a required drug test.

He has since had one of the biggest comebacks in Hollywood history, and this year topped Forbes highest-paid actor list, reportedly eaing $US50 million ($A53.36 million) for playing Tony Stark in the third Iron Man movie.