Detecting the Invisible: How We Know What Ancients Consumed
Plants containing psychoactive properties used by ancient populations are well documented within the archaeological record, covering most of the world. Ancient drug use is clear to have served various roles, such as medicinal, spiritual, religious, recreational, and social. Evidence of key psychoactive plants includes tobacco, psilocybin, ayahuasca, snuffs, opium and cannabis, and others.
Biomolecular techniques enable archaeologists to detect and characterise organic compounds in archaeological remains. Chemical residue samples from human remains (most commonly dental calculus, nails and hair) and various artefacts can detect the presence of psychoactive alkaloids. Advances in analytical chemistry, combined with contextual archaeological evidence, make it possible to uncover the significance of ancient drug use in social, symbolic and practical manners. Associating specific plant types with individuals or artefacts of a particular population can provide a wider understanding of how and why ancient populations utilised such psychoactive substances.
Residue analysis provides direct evidence of psychoactive substance use in ancient populations. Along with radiocarbon dating and historical documents, it allows for the chronological dating and cultural trade placement of ancient drugs. The most common analytical techniques used in bioarchaeological are GC-MS and LC-MS, which enable the identification and quantification of alkaloids associated with psychoactive drugs.
How archaeologists uncover these secrets: Despite botanical evidence being rarely well-preserved for bioarchaeological analysis, artefacts which are linked to drug use (paraphernalia such as pipes, tubes, snuffing equipment and vessels), however, do often survive. Chemical analysis, particularly when remains are in a ritualistic context, signifies which psychoactive substances were used in ancient times, as well as the method of ingestion (e.g. smoking, inhaling or drinking). Modern mass spectrometry techniques are so sensitive that they can detect trace amounts of ancient compounds even after thousands of years, offering a chemical fingerprint of past practices that written records never captured.
Tracing Psychoactive Practices Across Civilizations
Mind-altering plants, like the opium poppy (Papaver somniferum) and cannabis (Cannabis sativa), are long associated with ancient ritual and religious practices. Residue analysis of Bronze-Age ceramic vessels excavated in Cyprus, Syria, Lebanon and Israel detected opium, suggesting used for all medicinal, cultural and ritualistic purposes (due to vessels found in a variety of contexts, signifying burial rites or offerings) [1]. Additionally, the vessels infer the movement of import trade from Cyprus to the Levant, suggesting that opium had a high economic value.
What this tells us about ancient trade: These Bronze Age findings reveal sophisticated trade networks spanning the Mediterranean, with opium serving as a valuable commodity much like precious metals or fine textiles. The presence of opium in both elite burial contexts and everyday settings suggests it was more accessible than previously thought, challenging assumptions about who had access to mind-altering substances in antiquity.
Dental calculus from two individuals in California tested positive for the presence of nicotine (an alkaloid of tobacco plants), LC-MS detected nicotine alkaloids, alongside strong contextual evidence of a pipe associated with one individual [2]. Similarly, chemical analysis of pipes from hunter-gatherer contexts identified traces of nicotine in such artefacts dated back to 1100BP [3]. These studies signify the importance of linking associated artefactual paraphernalia with chemical analysis to conclude intake methods and social information about individuals or populations.
Ayahuasca, a hallucinogenic beverage primarily consisting of Banisteriopsis caapi, is used in modern medicine in the treatment of depression and is commonly associated with rituals. LC-MS analysis of hair and nail samples of two Peruvian mummies detected coca alkaloids and ayahuasca metabolites, suggesting consumption of the beverage not long before death [4]. This implies that the Incan population may have intentionally utilised the antidepressant properties of ayahuasca, possibly concerning divination or spirituality. Archaeological studies associated with mummies allow interpretations related to elite individuals and, consequently, high status. These studies, therefore, suggest that associated psychoactive substances may have been more accessible for these individuals. However, GC-MS detection of nicotine and tryptamine alkaloids in the hair of Andean mummies (across different cultural periods) concluded that the consumption was present across society, irrespective of their wealth or social status [5], suggesting instead these psychoactive compounds had widespread access, rather than exclusivity to the elites which were represented by the mummies.
Another study utilising LC-MS/MS to analyse artefacts recovered from a Bolivian rock shelter (ca. 1000 CE, detected the presence of ayahuasca compounds [6]. For several millennia, various native plant species have been documented to be used in South America for their healing and psychoactive properties. The artefacts were interpreted to be part of the shamanic paraphernalia, representing spiritual and religious use. This contrasts with the previous study [7], where the same psychoactive substance, ayahuasca, was interpreted in a medicinal context rather than part of religious ceremonies, demonstrating the significance of context when interpreting bioarchaeological residue samples.
Recent discoveries expand the picture: In 2024, researchers uncovered the first physical evidence of hallucinogenic substances in a 2,000-year-old Egyptian vase depicting the deity Bes. Using advanced metabolomics and spectroscopy, they identified a complex mixture including wild rue (Peganum harmala), Egyptian blue lotus, honey, and other ingredients designed to induce dream-visions, likely used in fertility rituals and childbirth ceremonies. This discovery provides tangible proof of practices previously known only through mythology and art. Meanwhile, ongoing research at Peruvian sites continues to reveal sophisticated knowledge of psychoactive plant combinations, with evidence suggesting ancient peoples understood the synergistic effects of combining different compounds long before modern pharmacology existed.
Cannabis, one of the earliest cultivated plants in East Asia, is widely recognised for its medicinal, ritual and recreational purposes. GC-MS/MS analysis of wooden braziers from Western China (ca. 500 BCE) detected high levels of THC. This indicates that cannabis plants were burned during funerary ceremonies, possibly during a ritual to induce an altered state of mind during funerary rites [8]. This represents the deliberate use of psychoactive substances for recreational reasons in rituals and mortuary practice.
Understanding ancient knowledge systems: The diversity of substances detected across different cultures, from Mesoamerican psilocybin mushrooms to Andean vilca snuff, demonstrates that ancient peoples possessed sophisticated ethnobotanical knowledge. They understood which plants produced specific effects, how to process them for maximum potency, and when to use them for different purposes. This wasn't random experimentation but rather accumulated wisdom passed down through generations, often guarded by specialized practitioners like shamans or priests.
Where the Science Takes Us Next
Overall, the application of chemical analysis to archaeological remains reveals that the use of psychoactive substances in ancient times was widespread, with profound insights into the various medicinal, social and ritualistic purposes of ancient drugs. Despite the limited number of well-preserved case studies of well-preserved sites, it is clear that psychoactive substances date far back into ancient times, and the global distribution and diverse contexts signify the cultural heritage of psychoactive substances.
Many psychoactive alkaloids prove to be relatively stable and persist over thousands of years, allowing for their detection and quantification via GC-MS, LC-MS and other related analytical techniques. Through utilising bioarchaeological methods, and combining these with vital historical context and artifactual evidence, we can draw information about the significance of psychoactive substances to past populations and reconstruct the social impact, culture and mortuary practices, uncovering the well-established connections between psychoactive compounds and humans.
Looking forward: As analytical techniques continue to advance, researchers are now able to detect even smaller quantities of compounds and identify substances that were previously undetectable. This ongoing technological progress promises to reveal even more about humanity's long relationship with psychoactive plants. Future research combining chemical analysis with ancient DNA studies, isotope analysis, and advanced imaging may uncover not just what substances were used, but also how ancient peoples cultivated, traded, and selectively bred plants for specific psychoactive properties. Understanding these ancient practices offers valuable context for contemporary discussions about traditional plant medicines and their roles in human societies across time.
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Disclaimer: This article discusses psychoactive substances from a purely historical, archaeological, and scientific perspective. The content is intended for educational purposes only. Many substances mentioned in this article are controlled or illegal in various jurisdictions around the world. This article does not encourage, promote, or provide guidance on the use of any controlled substances. Readers should be aware that laws regarding these substances vary by country and region, and possession or use may result in legal consequences. The author and ReaxionLab assume no liability for health and/or legal outcomes resulting from the use of this information.