The son of actors Ryan O'Neal and Farrah Fawcett has pleaded not guilty to possessing heroin and a firearms charge.
Redmond O'Neal (26) will remain in custody until a hearing in Los Angeles later this month.
O'Neal's lawyer Richard Pintal said he hoped to reach a deal with prosecutors that included additional treatment for his client, who has had a string of drug arrests in recent years.
O'Neal, who faces nearly four years in prison if convicted, had stayed out of trouble for months before his arrest by Santa Monica police this week.
His car was stopped after officers said they saw him jump a red light, and a search of the vehicle uncovered the drugs, authorities said. Police said they found a 9mm handgun when they searched his apartment later.
Ryan O'Neal and Redmond's half-sister, actress Tatum O'Neal, attended yesterday's hearing.
Redmond was on probation for an incident in which he brought drugs to a detention centre near LA. In that case, he was arrested in the car park while still under supervision for a previous drug arrest and an incident in which he and his father were arrested at the actor's Malibu home.
He was in jail in June 2009 when his mother died after a battle with cancer and was briefly released to attend her funeral.
O'Neal will return to court on August 24 for a probation violation hearing and to try to resolve the current case, Mr Pintal said.