Psychedelic rock is a style of rock music popular in the late 1960s that was largely inspired by hallucinogens, or so-called "mind-expanding" drugs such as marijuana and LSD, and that reflected drug-induced states through the use of feedback, electronics, and intense volume.

Emerging in 1966, psychedelic rock became the soundtrack of the wider cultural exploration of the hippie movement. initially centred to the west coast of the united states. 

After the grateful dead band psychedelia soon spread from the San Francisco Bay area to the rest of the country and then to Europe to become the major rock phenomenon of the late 1960s.