NEW YORK — Heath Ledger died from an accidental overdose of six different drugs — painkillers and sedatives — the medical examiner said Wednesday, leading doctors to warn of the dangers of mixing prescription drugs.

The 28-year-old film star died “of acute intoxication” from the combination of two strong painkillers, two anti-anxiety medicines and two sleeping aids, according to the medical examiner’s office.

Among the drugs found in his body were oxycodone, a painkiller sold as OxyContin and used in other pain relievers such as Percodan and Percocet. Others included drugs sold as anti-anxiety pills Valium and Xanax, which are sedatives.

The medical examiner and police wouldn’t identify the medications Ledger had in his apartment when his body was discovered on Jan. 22, nor would they discuss who had prescribed them. It also wasn’t known why he had the drugs; he said in a newspaper interview last year that he needed sleeping pills after two stressful acting jobs.

The Drug Enforcement Administration is investigating how Ledger got the medications. It’s common for investigators to review prescriptions when so many drugs are involved in an overdose death, said spokesman Rusty Payne.

Doctors not connected with the case said it would be unlikely for one doctor to order all the drugs. However, they said it’s not unusual for people to be prescribed both painkillers and sedatives, and overdoses are not uncommon.

“This is not rock star wretched excess,” said Cindy Kuhn, a pharmacology professor at Duke University. “This is a situation that could happen to plenty of people with prescriptions for these kind of drugs.”

Kuhn said some of the drugs are long-lasting and Ledger could have taken them over a period of several days. The medical examiner’s office wouldn’t say what concentrations of each drug were found in Ledger’s blood.

“What you’re looking at here is the cumulative effects of these medications together,” said the spokeswoman, Ellen Borakove.

Police had said they found six bottles of anti-anxiety medicines, sleeping pills and other medicine in his Manhattan apartment after the Oscar-nominated actor was discovered dead in his bed last month.

“This was not a deliberate attempt to kill himself. This was an accident,” said Lawrence Kobilinsky, head of forensic science at John Jay College in New York. He had no role in the investigation. “He just took too many drugs having similar effects on the central nervous system.”