Archaeological investigations in northeast Mexico and Trans-Pecos, Texas have shown that the use of psychotropic drugs in this region goes back to around 8500 BC. The aboriginal inhabitants of this region used the mescal bean, Sophora secundiflora, and buttons from the peyote cactus, Lophophora williamsii1.
From an archaeological site in Coahuila, Mexico, several peyote buttons were retrieved and radiocarbon-dated to AD 810–1070. Alkaloid analysis revealed the presence of mescaline and four related tetrahydroisoquinoline alkaloids2. We have, however, analysed two much older samples of peyote buttons. These samples are thought to have been found in Shumla Cave number five on the Rio Grande, TX, USA, and are in the collection of the Witte Museum in San Antonio3. Radiocarbon dating showed a mean age of 5700 years.
Standard alkaloid extraction procedures done on the samples gave residues that were analysed by thin-layer chromatography and gas chromatography-mass spectrometry. We were able to identify mescaline in both samples, based on identical retention times and Rf values, and similar mass-to-charge ratios and fragmentation pattern. The detection of mescaline in two different samples, both analysed by two methods based on different principles, is reliable evidence for the presence of this psychotropic drug.
Freshly prepared peyote buttons can contain up to 8% of total alkaloids. The previously studied 1000-year-old sample had a lower content, around 2·25%. In our analysis, alkaloid content had fallen to 2%, and mescaline was the only peyote alkaloid we could identify. There was no trace of any of the other tetrahydroisoquinoline alkaloids typical for peyote.
Earlier, nicotine and caffeine had been identified in plant remains from a medicine man's tomb in Bolivia, aged 1600 years4. Morphine has been found in a 3500 year old ceramic container from Cyprus5.
From a scientific perspective, the studied peyote material seems to be the oldest plant drug that yielded a major bioactive compound on chemical analysis. From a cultural point of view, our identification of mescaline strengthens the evidence that Native Americans already recognised and valued the psychotropic properties of peyote as long as 5700 years ago.