The drivers of both cars were arrested on suspicion of DUI after the crash, which was reported at 12:39 a.m. at 10th and Howard streets, police Sgt. Daryl Fong said.
Fong said a van containing two people was speeding south on 10th Street when it ran a red light and struck a sedan that had six people in it.
All eight people involved in the crash were taken to hospitals with serious but not life-threatening injuries, he said.
The drivers of both vehicles were arrested on suspicion of driving under the influence, and the other occupant of the van was also arrested for possession of suspected cocaine, Fong said.
The van may have also been involved in a hit-and-run in the city's Northern Police District shortly before the crash, but that has not yet been confirmed, Fong said.