Star Wars actress had taken heroin before she died
Carrie Fisher's post-mortem report showed the actress had cocaine in her system as well as traces of heroin and ecstasy when she fell ill on a plane last year.
However, investigators could not determine what impact the drugs may have had on her death.
The report, released yesterday, said Fisher may have taken cocaine three days before the December 23 flight on which she became ill. She died aged 60 four days later.
It also found traces of heroin and MDMA, which is also known as ecstasy, but it could not be determined when Fisher had taken those drugs.
The findings were based on toxicology screenings done on samples taken when the Star Wars actress arrived at a Los Angeles hospital.
Coroner's officials ruled Fisher died from sleep apnoea and a combination of other factors.
A news release issued last week mentioned drugs were found in Fisher's system, but it did not provide details.
The full report contains a detailed explanation of the results, such as why investigators believe Fisher took cocaine at least three days before her flight.
"At this time the significance of cocaine cannot be established in this case," the report states.
It also states that, while heroin is detectable in the system for a briefer period of time, investigators could not determine when Fisher took it or the ecstasy.
"Ms Fisher suffered what appeared to be a cardiac arrest on the aeroplane, accompanied by vomiting and with a history of sleep apnoea," the report said.
"Based on the available toxicological information, we cannot establish the significance of the multiple substances that were detected in Ms Fisher's blood and tissue, with regard to the cause of death."
Among the factors that contributed to Fisher's death was a build-up of fatty tissue in the walls of her arteries, the coroner's office said.
Toxicology tests also found other opiates in her system, including morphine, though the report states that could have been a by-product of heroin.
A phone message left for Fisher's brother, Todd, was not immediately returned.
He said on Friday that he was not surprised that drugs may have contributed to his sister's death.
"I would tell you, from my perspective, that there's certainly no news in Carrie doing drugs," he said.
He noted that his sister wrote extensively about her drug use, and that many of the drugs she took were prescribed by doctors to try to treat her mental health conditions.
Fisher had long battled drug addiction and mental illness. She said she smoked pot at 13, used LSD by 21 and was diagnosed with bipolar disorder at 24.
"I am not shocked that part of her health was affected by drugs," Todd Fisher said.
He said his sister's heart condition was probably worsened by her smoking habit, as well as the medications she took.
"If you want to know what killed her, it's all of it," he added.