The Soma Mystery: What Were the Vedic Priests Drinking?

Somewhere on the high steppe — the vast grassland corridor stretching from the Black Sea east toward the Altai Mountains — a priest is pressing stones together. Between the stones is a plant. Out of the plant flows a liquid, golden or tawny, which runs through a filter made of sheep’s wool. The filtered liquid is mixed with milk, or with water, or with both. It is poured into wooden cups. The priest chants. The fire crackles. The gathered people — warriors, herders, families of the clan — watch the preparation with an attention that is not curiosity. It is reverence. It is need.

The priest drinks. The warriors drink. And then something happens that the priests will spend the next three centuries writing hymns about.

This is a scene we cannot verify and cannot dismiss. We know it happened because the hymns survived — 1,028 of them, collected in the Rigveda, the oldest scripture in Hinduism and one of the oldest religious texts in any human language. We know the drink was called Soma. We know it was more important than almost anything else in the Vedic world. What we do not know — what no one has known for roughly two thousand years — is what it was.

The Soma mystery is the oldest unsolved question in the history of psychoactive substances. It may also be the most important. Because whatever was in that cup, it helped build a religion that now claims over a billion adherents, shaped a philosophical tradition that influenced every subsequent civilization it touched, and gave us some of the most ecstatic descriptions of altered consciousness ever committed to language.

And then it disappeared. Completely.

The God That Was Also a Drink

The Rigveda is organized into ten books, called mandalas. The Ninth Mandala — all 114 hymns of it — is devoted entirely to Soma. Not to the god Indra, king of the heavens, who gets about 250 hymns. Not to Agni, the fire god, who gets about 200. The Ninth Mandala is about Soma, and the word “about” doesn’t capture it. The Ninth Mandala is a love letter. It is a technical manual. It is an act of worship directed at a substance that the poets regarded as simultaneously a plant, a drink, a god, and the direct experience of the divine.

This is the part that stops Western readers cold. In the Vedic world, Soma was not a drug used to contact a god. Soma was the god. The pressing of the plant was a divine act. The filtration through wool was a cosmic purification. The drinking was communion in the most literal sense available to language — you drank the god, and the god entered you, and the boundary between worshipper and worshipped dissolved.

The central hymn, Rigveda 8.48, is one of the most famous passages in all of ancient literature:

We have drunk Soma and become immortal; we have attained the light, the Gods discovered. Now what may foeman’s malice do to harm us? What, O Immortal, mortal man’s deception?

“We have drunk Soma and become immortal.” Not “we will become immortal in the afterlife.” Not “we believe in immortality.” We have become immortal. Past tense. Accomplished. Done. Whatever was in the cup, the experience of drinking it was so overwhelming, so self-evidently real, that the poet does not argue for its significance. He reports it.

Other hymns describe the effects with a specificity that makes pharmacologists lean forward:

In wild joy thou art spread over every limb; in our limbs, Soma, thy bliss is felt. The heavens and the earth themselves have not grown equal to one half of me. Have I not drunk Soma? I am become great. Have I not drunk Soma? I have gone to the sky.

Grandiosity. Physical euphoria spread through the body. A sense of cosmic expansion. The feeling that the self has grown beyond all normal boundaries. These are not vague spiritual sentiments. These are descriptions of a psychoactive experience, written by people who were trying to capture in words something that words could barely hold.

The pressing itself is described in loving, ritualistic detail. Soma is pressed between stones — the verb su (to press, to extract juice) is the root of the word Soma itself. The juice is golden or tawny. It is filtered through wool. It is mixed with milk. Multiple hymns describe it as arriving by eagle — brought from the mountains, from a high place, from the realm of the gods. The plant grows in the mountains. It must be procured. It is not common.

And then, at some point between the composition of the Rigveda (roughly 1500-1200 BCE) and the later Vedic texts, the original Soma plant was lost.

The Disappearance

This is the heart of the mystery, and it is strange enough to be worth stating plainly: the most important sacramental substance in Vedic religion — the substance around which the entire ritual practice revolved, the substance that warranted more hymns than any god except Indra — vanished.

The later Vedic texts — the Brahmanas, the Sutras, the commentaries compiled between roughly 800 and 200 BCE — make this explicit. They discuss substitute plants. They describe rituals in which symbolic Soma replaces the real thing. The Shatapatha Brahmana, one of the most important prose commentaries on Vedic ritual, names specific substitute plants and acknowledges, with something that reads like theological embarrassment, that the original is no longer available.

The most likely explanation is geographical. The Vedic people migrated. The Indo-Aryan cultures that composed the Rigveda originated in the Central Asian steppes — somewhere in the region of modern Kazakhstan, Uzbekistan, or the Pontic steppe north of the Black Sea. Over centuries, they moved south and east, through Afghanistan and the mountain passes, into the Indian subcontinent. As they moved, they left behind the ecosystem where the Soma plant grew.

Whatever Soma was, it was a mountain plant of Central Asia. When the Vedic people settled in the Indus Valley and the Gangetic plain, they could no longer find it. They tried substitutes. They remembered the hymns. But the plant itself — the actual, physical source of the experience described in Rigveda 8.48 — was gone.

By the time of the Upanishads and the classical Hindu period, Soma had become entirely mythological. The drink that had been the living center of Vedic religion became a symbol, a memory, a god without a body. The rituals continued in symbolic form. The experience they originally facilitated did not.

This is one of the great losses in religious history. Imagine if Christianity had lost the recipe for communion wine and spent the next three thousand years trying to figure out what grapes were.

The Candidates

The question “What was Soma?” has consumed scholars since the eighteenth century. Dozens of candidates have been proposed. Five deserve serious attention.

1. Amanita muscaria: The Red Mushroom Theory

In 1968, R. Gordon Wasson — the same banker-turned-ethnomycologist who had participated in Maria Sabina’s velada in Mexico and introduced psilocybin mushrooms to the Western world through Life magazine in 1957 — published Soma: Divine Mushroom of Immortality. It was his most ambitious work, and it proposed the most dramatic answer: Soma was Amanita muscaria, the fly agaric mushroom.

The case was not unreasonable. Amanita muscaria is the iconic red-capped mushroom with white spots — the mushroom of fairy tales, the mushroom of Alice in Wonderland, the most visually recognizable fungus on Earth. It grows in symbiosis with birch and pine trees across the northern temperate zone, including Central Asia. It is psychoactive, containing muscimol and ibotenic acid. It has a documented history of ritual use among Siberian peoples — the Koryak, the Kamchadal, the Chukchi — who consumed it in shamanic ceremonies.

Wasson assembled an impressive body of circumstantial evidence:

The color. Multiple Rigvedic hymns describe Soma as hari — golden, tawny, reddish. The cap of Amanita muscaria is bright red, fading to orange and golden as it matures and dries. Wasson argued that the color descriptions in the hymns matched the mushroom’s life cycle.

The mountains. Soma comes from the mountains, brought by an eagle. Amanita muscaria grows at altitude, in mountain forests. It does not grow on the plains where the Vedic people eventually settled — which would explain why the original plant was lost during the migration south.

The pressing. The hymns describe pressing Soma between stones to extract juice. Wasson argued that dried Amanita muscaria caps could be crushed between stones and reconstituted with water, and that this was what the “pressing” described.

The urine recycling. This is the detail that made headlines and turned stomachs. Several Rigvedic hymns contain references that, Wasson argued, describe the practice of drinking the urine of a person who has consumed Soma. Amanita muscaria's active compounds — muscimol particularly — pass through the body largely unmetabolized. The urine of a person who has consumed the mushroom is itself psychoactive, sometimes more potently so than the original dose (the body filters out some of the nauseating ibotenic acid while the muscimol passes through). This practice is well-documented among Siberian peoples. Some passages in the Rigveda — references to Soma “flowing” through the body and being “passed” onward — could be read as euphemistic descriptions of urine recycling.

The problems are significant:

The effects don’t match. Amanita muscaria produces a range of effects including drowsiness, nausea, muscle twitching, delirium, and — at appropriate doses — a dreamy, dissociative altered state. What it does not typically produce is the soaring, ecstatic, “I have become immortal” rapture described in the Rigvedic hymns. The pharmacological profile of muscimol — a GABA-A agonist that produces sedation and delirium — is categorically different from the pharmacological profile of tryptamine psychedelics (psilocybin, DMT) or empathogens (MDMA), which more closely match the Vedic descriptions.

The toxicity. Amanita muscaria causes nausea and vomiting in a significant percentage of users. The Rigvedic hymns, while extensive in their description of Soma’s effects, do not describe purging. A substance that made warriors vomit before battle would be an odd choice for a martial sacrament.

The identification gap. Wasson’s argument depends on reading certain Vedic descriptions metaphorically (the “pressing” as reconstitution, the color descriptions as approximate) while reading others literally (the mountain origin, the possible urine references). This selective literalism is a weakness.

Wasson’s thesis remains the most famous answer to the Soma question. It is not, forty years later, the most convincing.

2. Psilocybe Mushrooms: The Tryptamine Alternative

A smaller body of scholarship has proposed that Soma was a psilocybin-containing mushroom rather than Amanita muscaria. Psilocybe cubensis and related species grow in the dung of cattle, which were central to Vedic pastoral life. The effects of psilocybin — euphoria, visual and auditory enhancement, a sense of cosmic connection, the dissolution of ego boundaries, experiences frequently described as encounters with the divine — match the Rigvedic descriptions far more closely than muscimol does.

The case for psilocybin rests primarily on pharmacological fit rather than direct evidence:

The effects. “We have drunk Soma and become immortal; we have attained the light, the Gods discovered.” This is, almost precisely, what participants in modern psilocybin studies at Johns Hopkins describe: a sense of having contacted something absolute, an encounter with a reality more fundamental than ordinary consciousness, an experience so self-evidently real that it requires no defense.

The cattle connection. Psilocybe cubensis grows on cow dung. The Vedic people were cattle herders. The cow was sacred. A psychoactive mushroom that emerged from sacred cow dung would have carried enormous theological significance — the divine literally sprouting from the most revered animal.

The problems are also significant:

No direct textual support. The Rigvedic descriptions of Soma do not obviously describe a mushroom. There are no references to a cap, a stem, gills, or any other morphological feature recognizable as a mushroom. The “pressing between stones” makes less sense for a mushroom than for a plant with rigid stems or a fleshy cap.

Limited geographical evidence. While Psilocybe cubensis is found worldwide today, its historical distribution in the Central Asian steppes during the Vedic period is uncertain.

No urine activity. Psilocybin does not pass through the body in psychoactive form. The possible urine-recycling references in the Rigveda, if that’s what they are, would not apply to psilocybin.

The psilocybin theory explains the experience of Soma better than any other candidate. It explains the botany less well.

3. Ephedra: The Conservative Answer

David Flattery and Martin Schwartz, in their 1989 book Haoma and Harmaline, proposed that Soma (and its Iranian cognate Haoma) was Ephedra, a genus of shrubby plants native to Central Asia. Ephedra contains ephedrine and pseudoephedrine — stimulant alkaloids that increase heart rate, elevate mood, and produce a feeling of energy and alertness.

The case for Ephedra is based primarily on continuity:

The Iranian parallel. The Avestan tradition — the Zoroastrian scriptures, linguistically and culturally related to the Vedic — has its own sacred drink, Haoma, clearly cognate with Soma. Modern Zoroastrian ritual uses Ephedra as the Haoma plant. If the Iranian tradition preserved the original identification, then Soma may have been Ephedra all along.

Botanical fit. Ephedra grows abundantly across the Central Asian steppe. It is a jointed, woody plant whose stems can be pressed between stones to extract juice. The pressing described in the Rigveda fits Ephedra’s morphology well.

Archaeological evidence. Victor Sarianidi’s excavations at Gonur Tepe and other sites of the Bactria-Margiana Archaeological Complex (BMAC) in Turkmenistan found residues of Ephedra in vessels associated with ritual use, alongside cannabis and poppy, dating to approximately 2100-1700 BCE — the right time period and region for proto-Vedic culture.

The problem is devastating in its simplicity:

Ephedra is a stimulant. Its effects are comparable to a strong cup of coffee with an added edge of cardiovascular activation. It does not produce visions. It does not produce the ecstatic cosmic expansion described in Rigveda 8.48. It does not make you feel immortal. The Vedic poets did not devote 114 hymns and some of the most rapturous language in ancient literature to the experience of drinking a stimulant tea.

Ephedra may have been one component of a Soma preparation. It is almost certainly not the whole story.

4. Syrian Rue and a DMT Source: The Ayahuasca Analogue Theory

This is the most speculative candidate and, in some ways, the most pharmacologically elegant.

Peganum harmala — Syrian rue — grows abundantly across Central Asia, from Turkey to Mongolia. Its seeds contain harmala alkaloids: harmine, harmaline, and tetrahydroharmine. These are monoamine oxidase inhibitors (MAOIs). By themselves, they produce a mild psychoactive effect — some visual disturbance, dreaminess, nausea. But their primary pharmacological significance is that they inhibit the enzyme (monoamine oxidase) that normally breaks down DMT in the digestive system.

This is the same mechanism that makes ayahuasca work. Banisteriopsis caapi, the ayahuasca vine, contains the same class of harmala alkaloids as Syrian rue. The Amazonian genius of ayahuasca was combining an MAO inhibitor with a DMT source to create an orally active visionary brew. If the Vedic priests did the same thing — combining Syrian rue with a DMT-containing plant available in Central Asia — they would have produced a drink whose effects match the Rigvedic descriptions with startling precision.

DMT produces the most intense visionary experiences of any known psychoactive compound. Encounters with entities. Cosmic expansion. The absolute conviction of having touched something divine. “We have drunk Soma and become immortal” is, pharmacologically speaking, a very reasonable description of an oral DMT experience facilitated by an MAO inhibitor.

Some Rigvedic passages hint at a two-component preparation. References to Soma being “mixed” or “combined” could indicate that the drink involved more than one plant. The Ninth Mandala’s emphasis on filtration and purification might describe the process of preparing a complex brew rather than a simple extraction.

The problems:

No direct evidence. There is no archaeological evidence of harmala alkaloids or DMT in Vedic ritual contexts. The theory is built entirely on pharmacological reasoning, not textual or material evidence.

DMT source unclear. While DMT-containing plants exist in Central Asia (Arundo donax, various Acacia species), none has been convincingly linked to the Vedic period or region.

Speculative layering. The theory requires multiple assumptions: that the Vedic priests knew about two specific plants, understood their pharmacological synergy, developed a preparation method, and left no unambiguous record of the two-plant nature of the preparation.

It is an elegant hypothesis in search of evidence. The evidence may exist and simply hasn’t been found. Or the hypothesis may be wrong. This is what makes Soma a mystery and not merely a puzzle.

5. Cannabis: The BMAC Connection

Cannabis is the dark horse in the Soma race, supported less by textual analysis than by archaeology.

Victor Sarianidi’s excavations at Gonur Tepe and other BMAC sites in Turkmenistan found residues of cannabis alongside Ephedra and poppy in vessels associated with ritual use. The BMAC culture flourished from approximately 2300-1700 BCE in a region that many scholars believe intersected with proto-Indo-Iranian culture — the people who would eventually split into the Vedic Indians and the Avestan Iranians.

Cannabis produces euphoria, altered perception, relaxation, and — at higher doses — genuine psychoactive effects including visual disturbance and altered time perception. It grows abundantly across Central Asia. It has been used ritually in the region for thousands of years.

But the Rigvedic descriptions are a problem. Cannabis does not produce the ecstatic, visionary, “I have become immortal” experience that Soma apparently did. Cannabis makes you feel good. Soma, by every account, made you feel divine. These are different categories of experience.

The most plausible role for cannabis in the Soma question is as one component of a multi-plant preparation — contributing to euphoria and relaxation while another substance provided the visionary power. This possibility is not excluded by the evidence. It is simply not confirmed by it.

The Bigger Question: Why Does Every Civilization Have One?

Step back from the details of pressing stones and wool filters and golden juice and ask the question that the Soma mystery, regardless of its specific answer, forces into view:

Why does every ancient civilization seem to have a sacred substance?

The Vedic people had Soma. The Greeks had the kykeon at Eleusis. The Aztec and the Mazatec had teonanácatl. The Amazonian peoples had ayahuasca. The Bwiti of West Africa had iboga. The Native Americans had peyote. The San Pedro cactus appears in Andean art dating back three thousand years.

These are not the same substance. They are not the same culture. They are separated by oceans and millennia. But the pattern repeats with a consistency that demands an explanation.

One explanation is coincidence. Plants that alter consciousness grow on every continent. People found them. People used them. This is satisfying if you think of the pattern as parallel discovery, which it may be.

Another explanation is that the human brain is wired for this. The 5-HT2A serotonin receptor — the molecular lock that psilocybin, DMT, mescaline, and LSD all fit into — exists in every human brain. It was not put there by mushrooms. It evolved for purposes that neuroscience has not fully elucidated. But its presence means that the human nervous system is, in a pharmacological sense, prepared for the class of experiences these substances produce. The lock exists. The keys are scattered across the plant kingdom. Every culture found a key.

A third explanation — the one the Vedic poets would have offered, the one Maria Sabina would have offered, the one the Eleusinian Hierophant would have offered — is that the sacred substances are not tools that humans discovered. They are communications that the sacred directed toward humans. The plants taught us. We were meant to find them. The experience they produce is not a side effect of pharmacology. It is the purpose.

Modern science cannot evaluate this third explanation. It is not a scientific claim. But it is a claim that every culture that developed a relationship with entheogenic substances independently arrived at. That convergence is, at minimum, interesting. What you make of it depends on what you think consciousness is and where you think it comes from.

(For a deeper look at this question — what happens when you name these substances as sacred rather than recreational — see our article on entheogens.)

What Modern Scholarship Says

The Soma question has not been settled by modern scholars. It has been refined.

Frits Staal, the Dutch-born scholar of Vedic ritual, spent decades analyzing the Soma ceremonies as performed with substitute plants in contemporary Vedic practice. His 1975 work documenting a twelve-day Soma ritual in Kerala (using a substitute plant, since the original had been lost for two thousand years) remains one of the most detailed ethnographic records of Vedic ritual. Staal argued that the ritual structure itself — the chanting, the fire offerings, the precise choreography of the priests — was the primary technology of transformation, and that the specific psychoactive substance was secondary.

This is a defensible position, and it has parallels in modern psychedelic research. Set and setting matter as much as the molecule. A ritual context amplifies and shapes the psychoactive experience. But Staal’s position also sidesteps the obvious: the Vedic poets wrote 114 hymns about the drink, not about the ritual. Whatever Soma was, the experience of consuming it was the thing that mattered most.

Terence McKenna, in Food of the Gods (1992), argued for psilocybin, embedding the Soma question within his broader thesis that psychedelic plants drove the evolution of human consciousness. McKenna’s ideas are more stimulating than rigorous — he was a storyteller first and a scientist second — but his pharmacological argument (that psilocybin’s effects match the Vedic descriptions better than any other candidate) remains strong, even as his evolutionary claims remain unproven.

The Flattery and Schwartz Ephedra thesis, while botanically and archaeologically grounded, fails on the experiential level. Sarianidi’s BMAC evidence for multi-plant preparations — Ephedra plus cannabis plus poppy — opens the possibility that Soma was not a single substance but a complex brew whose composition varied by region and period. This would explain both the range of descriptions in the Rigveda and the difficulty of identifying a single candidate.

The honest summary is this: we do not know what Soma was. We may never know. The plant was lost to geography and time. The priests who knew the secret are three thousand years dead. What survives are the hymns — and the hymns describe something extraordinary. Something that made warriors feel invincible and poets feel divine. Something that dissolved the boundary between human and god in a way that 114 hymns could not adequately capture but could not stop trying to.

The Cup and the Question

The Soma mystery is, finally, a mystery about loss. Something was known and is no longer known. Something was experienced and can no longer be experienced in its original form. The cup is empty. The hymns remain.

But the hymns do something remarkable: they preserve, across three and a half millennia, the quality of the experience even as the cause is lost. You do not need to know what Soma was to feel, reading Rigveda 8.48, that the poet is describing something real. The language has the texture of testimony, not theology. This is a person telling you what happened to them. What happened to them was enormous.

And this is what connects the Soma mystery to the present moment. The experience the Vedic priests described — the dissolution of ordinary consciousness, the sense of contact with something absolute, the conviction of having touched immortality — is not locked in the past. It is being produced, today, in clinical settings at Johns Hopkins, Imperial College London, and research institutions across the world, using psilocybin. The descriptions match. The awe matches. The difficulty of putting the experience into adequate language matches.

We may never identify the Soma plant. But we have identified the experience. It is written in the oldest hymns of the oldest scripture in one of the world’s oldest religions. It is being measured, right now, by fMRI machines and psychometric scales. The gap between the two — between the pressed juice in the Vedic fire ceremony and the synthetic psilocybin in the clinical trial — is filled with three thousand years of searching.

The cup is being refilled. Whether it contains the same drink is a question that pharmacology cannot answer and poetry cannot stop asking.

This article is part of Kind Stranger’s Ancient Roots series, exploring the deep history of psychoactive plants and fungi in human civilization. For the full story of R. Gordon Wasson — who proposed the Amanita muscaria theory and also introduced psilocybin to the West — see Maria Sabina and the Velada. For the ceremony that may have used ergot alkaloids for two thousand years in ancient Greece, see The Eleusinian Mysteries. For the science of psilocybin itself, see our psilocybin guide.