The school district said a staff member called authorities around lunchtime when the seventh-grade teacher began showing signs of being intoxicated.
"He was right next to the class that it happened in, and he came and he told me what had happened. But they just had told him that she had taken some pills and she had fainted," said Elizabeth Godinez, whose son attends the school.
When deputies arrived, Neff was being treated by a school nurse in the administration building. Investigators believe Neff took prescription drugs combined with alcohol. Deputies found a container filled with an alcoholic beverage on campus.
"It's very shocking," said Riverside County Sheriff's deputy Herlinda Valenzuela. "You don't expect this, to send your child to school and then find out that the teacher was arrested for being intoxicated."
Neff was transferred to John F. Kennedy Memorial Hospital in Indio for treatment, then booked at the Sheriff's Indio station on suspicion of felony child endangerment.
School district officials said this was Neff's frist year teaching at Toro Canyon. She oversees about 100 students during the school day.
"Parents need to be assured that we were proactive in this situation, and at no time were students ever in any danger," said Ricardo Z. Medina, superintendent of the Coachella Valley Unified School District.
Neff has been placed on leave, but district officials did not say whether she'll be paid during the absence.