She was 68.
Her friend, Dawna Sodders, told the Los Angeles Times that Fairchild died of liver cancer on Tuesday at a convalescent home.
Fairfield's work included 1974's "Thunderbolt and Lightfoot" starring Clint Eastwood, and as an Ajax-snorting druggie in "Up in Smoke."
Fairchild once dated Danny Hutton of Three Dog Night and is credited with suggesting the group's name.
Drugs and alcohol derailed her career in the 1970s. The Times said she spent time in rehab and jail and was robbed and raped while living on the street before going clean.