How did The Rev really die?

It says on the internet that "the cause of death was revealed to have been an acute polydrug intoxication due to combined effects of oxycodone (OxyContin), oxymorphone (a metabolite of oxycodone), diazepam (Valium), nordiazepam (a metabolization of diazepam) and ethanol." i dont exactly know what that means so can some just break it down for me?