The actor was travelling on a motorway in Orange County when the crash happened.
Captain Larry Kurtz of the Orange County Fire Authority told the Press Association: “It happened at 10.55 last night on the northbound 5 freeway at Alicia Parkway. The vehicles involved were a limo-type SUV and a small sedan.
“There were four patients. One female in her 20s and three males in their 40s and 50s.
“Three patients considered to have minor injuries were taken to local hospitals.
“One patient was deemed to be a critical trauma and was transferred to an area trauma centre.
“California Highway Patrol is investigating the incident.”
Mr Kurtz said he could not identify patients because of confidentiality issues.
Photos of the crash on US website TMZ show the Hollywood star talking on a mobile phone as he is carried on a stretcher.
A representative for Ferrell has been contacted for comment.