Al Gore III, 24, was driving a blue Toyota Prius about 100 mph on the San Diego Freeway when he was pulled over at about 2:15 a.m., Sheriff's Department spokesman Jim Amormino said.
The deputies said they smelled marijuana and searched the car, Amormino said. They found less than an ounce of marijuana along with Xanax, Valium, Vicodin and Adderall, which is used for attention deficit disorder, he said.
"He does not have a prescription for any of those drugs," Amormino said.
Gore was being held in the men's central jail in Santa Ana on $20,000 bail.
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Kalee Kreider, a spokeswoman for his parents, did not immediately return phone messages to The Associated Press on Wednesday.
The son of the former vice president and Democratic presidential nominee also was pulled over and arrested for pot possession in December 2003, in Bethesda, Md., while he was a student at Harvard University.
He completed substance abuse counseling as part of a pretrial diversion program to settle those charges.
The youngest of Al and Tipper Gore's four children and their only son, Gore lives in Los Angeles and is an associate publisher of GOOD, a magazine about philanthropy aimed at young people.