The crash happened about 6 a.m. near Main Street, according to the Los Angeles Fire Department.
The condition of the injured patient was unknown, and it was unclear if that person was an occupant of the semitrailer or the damaged car.
Semitruck carrying 50,000 pounds of cookie dough overturns in Cajon Pass
Following the crash, southbound traffic was diverted at Broadway. Lanes have since reopened.
The cause of the crash is under investigation.