what were they?
LSD, alcohol.
Jimi Hendrix
Roby and Schreiber assert that Hendrix first used LSD when he met Linda Keith in late 1966. 
which agency investigated the death of jimi hendrix? Scotland Yard. what was said in the post mortem report? Hendrix was "well nourished and muscular", and he identified a quarter-inch scar on Hendrix's left wrist. He said that there were "no stigmata of [intravenous] drug addiction. what is the background of his death? On September 11, 1970, Hendrix gave his final interview in his suite at the Cumberland Hotel in London,Hendrix confirmed reports that Billy Cox, the bass player in his band, the Jimi Hendrix Experience, was leaving. where did he die? London. what was his profession? Guitarist/Musician. did he have any addictions? Yes, he did.
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Jimi Hendrix [SEP] Drugs and alcohol
Roby and Schreiber assert that Hendrix first used LSD when he met Linda Keith in late 1966. Shapiro and Glebbeek, however, assert that Hendrix used it in June 1967 at the earliest while attending the Monterey Pop Festival. According to Hendrix biographer Charles Cross, the subject of drugs came up one evening in 1966 at Keith's New York apartment. One of Keith's friends offered Hendrix "acid", a street name for LSD, but Hendrix asked for LSD instead, showing what Cross describes as "his naivete and his complete inexperience with psychedelics". Before that, Hendrix had only sporadically used drugs, experimenting with cannabis, hashish, amphetamines, and occasionally cocaine.