what was the cause of his death?
It was  caused by "acute mixed drug intoxication, including heroin, cocaine, benzodiazepines, and amphetamine".
Philip Seymour Hoffman
 caused by "acute mixed drug intoxication, including heroin, cocaine, benzodiazepines, and amphetamine". 
who was the dude in the big lebowski Jeffrey Lebowski is it a film or a series? A crime comedy film who are the actors in it? Jeff Bridges, Julianne Moore, Steve Buscemi, David Huddleston, John Turturro and Philip Seymour Hoffman where was it filmed? Los Angeles when did the last actor make his acting debut? He made his screen debut in 1991, in a "Law & Order" episode called "The Violence of Summer" has he been to acting school? Yes, He received a drama degree in 1989. which other films was he a part of? "The Savages", "Synecdoche, New York", "Twister"
wiki:5016240
Philip Seymour Hoffman [SEP] Death and legacy
Although friends stated that Hoffman's drug use was under control at the time, on February 2, 2014, Hoffman was found dead in the bathroom of his Manhattan apartment by a friend, playwright and screenwriter David Bar Katz. Hoffman was 46. Detectives searching the apartment found heroin and prescription medications at the scene, and revealed that he was discovered with a syringe in his arm. After an investigation including the Manhattan Assistant District Attorney Alex Spiro, Hoffman's death was officially ruled an accident caused by "acute mixed drug intoxication, including heroin, cocaine, benzodiazepines, and amphetamine". Whether Hoffman had taken all of the substances on the same day, or whether any of the substances had remained in his system from earlier use, was not reported.