Lil Peep Toxicology Report Shows Fentanyl, Xanax Overdose (UPDATE)

Lil Peep died from an overdose of Fentanyl and Xanax, according to the toxicology report ... TMZ has learned.

The Pima County Medical Examiner conducted the testing and found the cause of death came from the "combined toxic effects of fentanyl and alprazolam." Alprazolam is generic form of the anti-anxiety drug Xanax.

There were a ton of other drugs in his system though. According to the report, obtained by TMZ, he tested positive for marijuana, cocaine and the painkiller Tramadol in his blood. His urine tested positive for all those drugs, plus other powerful opiates such as Hydrocodone, Hydromorphone (Dilaudid), Oxycodone and Oxymorphone. He had no alcohol in his system.

The M.E. says the death was accidental. It's known that combining Fentanyl and Xanax can cause respiratory distress, coma and possibly death.

As we reported, the 21-year-old rapper was found dead on his tour bus during a stop in Tucson, Arizona. He was unresponsive and they were unable to revive him.