At about 3:25 p.m., Heidi Reid, 35, was driving a Mitsubishi Gallant west on Chileno Valley Road at about 55 mph when she approached an eastbound Honda Civic driven by Aran Harris.
The Mitsubishi crossed the center divide and crashed into the Honda, according to the CHP.
Because Reid was not properly wearing her seatbelt, she suffered major facial lacerations and abrasions.
Harris suffered internal and leg injuries.
Both Reid and Harris were transported to Santa Rosa Memorial Hospital, where Reid was placed under arrest, according to the CHP.