As did the Beats before them, most hippies used
cannabis, which they considered pleasureful and benign. They enlarged their repertoire of recreational drugs to include hallucinogens such as LSD, psilocybin, and mescaline.
On the East Coast of the United States, Harvard professors Timothy Leary and Richard Alpert advocated the use of psychotropic drugs for religious purposes. Regarding LSD, Leary said, "Expand your consciousness and find ecstasy and revelation within.".
On the West Coast of the United States, Ken Kesey was an important figure in promoting the recreational use of psychotropic drugs, especially LSD, also known as "acid." By holding what he called "Acid Tests," and touring the country with his band of Merry Pranksters, Kesey became a magnet for media attention that drew many young people to the fledgling movement. The Grateful Dead played some of their first shows at the Acid Tests, often as high on LSD as their audiences. Kesey and the Pranksters had a "vision of turning on the world."
Harder drugs, such as amphetamines and the opiates, were also used in hippie settings; however, these drugs were disdained, even among those who used them, because they were recognized as harmful and addictive. Heroin, for example, was banned from the Stonehenge Free Festival.