Echinopsis pachanoi has a long history of being used in Andean traditional medicine. Archeological studies have found evidence of use going back two thousand years, to Moche culture. [1] Although Roman Catholic church authorities after the Spanish conquest attempted to suppress its use,[2] this failed, as shown by the Christian element in the common name “San Pedro cactus” – Saint Peter cactus. The name is attributed to the belief that just as St Peter holds the keys to heaven, the effects of the cactus allow users “to reach heaven while still on earth.”[3]

San Pedro is 93.5% water by weight. 0.025%+ of Mescaline trace amount of tyramine, 0.01% of 3-Methoxytyramine by dry weight, Trace amount of Hordenine, 3,4-Dimethoxyphenethylamine, 3-Hydroxy-4,5-dimethoxyphenethylamine, 4-Hydroxy-3,5-dimethoxyphenethylamine , anhalonidine and anhalinine [4] [5] [6].

In 1888 Louis Lewin published in Berlin the first chemical paper on peyotl (Lewin 1888). This caused a sensation, as entheogenic plants had hitherto been unknown to European scientists. Lewin reported the isolation of an alkaloid, which he named Anhalonin (today considered to have been likely a mixture of alkaloids); this was the first published report of alkaloids from the Cactaceae. Lewin had obtained dried peyotl from the u.s. pharmaceutical firm Parke, Davis and Co. during a trip to the U.S. in 1887. Other scientists became interested in peyotl, and phytochemical work on the plant culminated in 1895 and 1896, when German chemist Arthur Heffter isolated four pure alkaloids from the plant, one of which he named Mezcalin, the others being Anhalonin, Anhalonidin and Lophophorin; he also described the isolation of Pellotin (or Peyotlin) from Lophophora Diffusa. Heffter was unable to detect visionary activity of his isolated alkaloids in animal experiments, which led him to employ the “Heffter Technique”, testing the alkaloids on himself, in an heroic series of self-experiments, which he summarised as follows [7]:

“Mezcalin hydrochloride, 0.15 g, produces a pattern of symptoms which differs in only a few respects from the one obtained with the drug [peyotl]. (Heffter 1898)“

The conclusive experiment took place on 23 November 1897, and this became the world’s first Mezcalin “trip” and the first entheogenic experiment with a purified compound. [7]

Nausea and mild abdominal cramps are often reported as side-effects, usually during the initial stages of the inebriation. Slight increase in body temperature is a common properties of mescaline experience. Peak effects are similar to those of psilocybin and LSD, being characterized by visual and auditory alterations, synaesthesia and ego dissolution, and the drug may show “cross-tolerance” with tryptamine class psychedelics. [2]