Heath died "as the result of acute intoxication by the combined effects of Oxycodone, Hydrocodone, Diazepam, Temazepam, Alprozalam and Doxylamine," a cocktail of sleeping medications, painkillers and anti-anxiety pills.
The drugs are the generic names for the painkiller OxyContin, the anti-anxiety drugs Valium and Xanax and the sleep aids Restoril and Unisom. Hydrocodone is another name for ibuprofen.
"We have concluded that the manner of death is accident, resulting from the abuse of prescription medications," the medical examiner's office said.
Heath, 28, was found dead in his Manhattan apartment on Jan. 22, several bottles of prescription drugs near his body. His grieving family, along with "heartbroken" Michelle Williams and their two-year-old daughter Matilda, will bury him Saturday in his hometown of Perth, Australia.