Actor Corey Haim, shown in March 2009 in Hollywood, Calif., had drugs in his system when he died but they did not play a part in his death, an autopsy found. (Michael Buckner/Getty Images)

Actor Corey Haim died from pneumonia complicated by an enlarged heart, bad lungs and narrowed blood vessels, the Los Angeles County coroner said Tuesday.

The coroner said drugs found in his system played no role in his death.

Haim, 38, died of natural causes from "community-acquired pneumonia," along with lung, heart and blood vessel problems, according to an autopsy report.

Low levels of eight drugs, including both prescription and over-the-counter medications, were found in his system along with marijuana, coroner's spokesperson Craig Harvey said.

"But nothing was at a level that would have contributed to his death," Harvey said.

The drugs included common cold and flu medications, such as ibuprofen and a cough-suppressant, he said.

Toronto-born Haim, who had struggled with drug problems throughout his life, died March 10 after collapsing in his mother's apartment. He was ill with flu-like symptoms before his death, and police said he was taking over-the-counter and prescription medications.

"The pneumonia is what killed him," Harvey said.

Haim was the star of 1980s films such as The Lost Boys, Lucas and License to Drive, but his career waned in the 1990s.

California Attorney General Jerry Brown said in April that Haim had been "doctor shopping" in the two months before his death and had obtained 553 prescription pills, including Valium, OxyContin and Vicodin.

Brown called Haim "a poster child for prescription drug abuse."

However, no OxyContin was found in his body, Harvey said. He noted that Haim's heart was abnormally large and factored in his death.

Haim also had damaged lungs and arteriosclerosis of his coronary arteries, with some vessels 50 per cent and even 75 per cent blocked.