Sage Stallone, the son of Sylvester Stallone, died of coronary artery disease, with coroner's officials suggesting that smoking might have played a role.
Coroner Chief Craig Harvey said that Sage had a history of being a heavy smoker, although family members have said the amount had diminished lately.
Sage Stallone died in July at the age of 36.
The coroner declared death by natural causes and the toxicology test came back "negative except for a sub-therapeutic level of hydrocodone."
The drug played no role in his death. A housekeeper found Stallone's body. According to reports, pills were found at the residence and investigators were trying to determine their source and whether they played any role in the death.
Instead, heart disease was the cause of death, and exactly what role, if any, smoking played in that is a question that may never be answered.
Sylvester also lost his half-sister, Toni-Ann Filiti, this week.