An LA coroner revealed that the singer, 48, had snorted a line of cocaine “immediately” before she drowned in a Beverly Hills hotel bathtub.
It is believed that Houston suffered a heart attack before slipping under the water in the bathtub and drowning.
The toxicology report suggested that “chronic use” of cocaine over time had led to the heart disease that contributed to her death by drowning.
The singer’s family said in a statement: “We are saddened to learn of the toxicology results, although we are glad to now have closure.”
Results from tests indicated that Houston suffered from heart disease that caused a 60 per cent narrowing of her arteries.
Assistant chief coroner Ed Winter said the condition is common in cocaine users.
“It just beats up their heart and they will have a heart attack,” he confirmed.
Houston was known to have battled drug addiction in the past, and was using crack cocaine at the height of her fame.