The demonstrators were protesting the dismantling of the "Occupy UC Davis" encampment that was set up in the school's quad area.
"Police came and brutalized them and tore their tents down and all that stuff. It was really scary. It felt like there was anarchy everywhere," said student Hisham Alihbob.
Police told Sacramento's KTXL TV station that the students were given until 3 p.m. Friday to remove their tents from the campus. When students refused, police arrived at the given time. Students sat down cross-legged and locked arms when cops showed up and the pepper spraying began.
UC Davis Police Chief Annette Spicuzza said it would not be safe or sustainable for demonstrators to camp in the quad.
"It's not safe for multiple reasons," Spicuzza said.
At least one woman left by ambulance for treatment of chemical burns.
"We just successfully booted the police off campus in a non-violent way," Chris Wong, a student protester who said he was speaking for himself, not the Occupy group, told the Sacramento Bee.
Wong said he was one of the students sprayed, but he looked down and didn't get a full dose. He said students then circled the police and tried to hold their ground. The police eventually left.