The coroner released its results Thursday.
Spokesman Craig Harvey says the primary cause of Murphy's death was pneumonia, with secondary factors of iron-deficiency anemia and multiple drug intoxication. Harvey says the drugs ingested were all prescription medications.
Harvey declined to say more about what types of drugs were involved. He says those details will be released in about two weeks when a complete report is ready.
Murphy died Dec. 20 at age 32 after collapsing at her Hollywood Hills home. Her mother and husband have said that the actress didn't abuse prescription medications or have an eating disorder.
Attempts to contact them Thursday were unsuccessful.