San Pedro, also known as Huachuma, Gigantón, agua collay, or Trichocereus/Echinopsis pachanoi, is a tall, thick columnar cactus held sacred by the indigenous peoples of the South American Andes due to its powerful spiritual medicinal, and visionary properties. Unlike its perhaps better-known psychedelic relative peyote, the San Pedro cactus is a fierce grower, and this feature makes it abundant both in the wild and as a cultivar despite a massive harvest for psychedelic use.
This cactus species is similar to other columnar cacti, especially its mescaline-containing relatives Peruvian torch (Trichocereus peruvianus) and Bolivian torch (Trichocereus bridgesii). It is a light, dark, or greyish-green color (which turns to yellow if it’s exposed to too much sunlight), usually with six to eight ribs, rarely as few as four (the most prized variety) or as many as nine. It’s mostly spineless, with short (up to 2 cm) thorns growing out from areoles on the ribs, which are up to 2 cm apart.
A strong San Pedro cactus sometimes grows in a tree-like or bush format, with multiple branches extending from the base or broken columns. It can grow up to a sizeable 6 m (20ft), with the largest recorded specimen being an incredible 12.2 m (40ft) tall; hence its Ecuadorian name Gigantón. Large white flowers sometimes blossom from the tops of the stems of old specimens. The flowers open during nighttime and last for a few days.
The San Pedro cactus is native to Ecuador and Peru, and can also be found growing in Bolivia, Chile, and Argentina. It lives in high altitudes of the Andean slopes—from 2,000 to 3,000 m (6,600 to 9,800ft). It is a hardy cactus, able to survive extremely low temperatures (down to -12 °C/10 °F) and a large range of humidity conditions; due to this, it is also successfully cultivated around the world.
The species is very easy to cultivate—all it needs is fertile soil and sunshine.
San Pedro cacti can be grown from seeds or a cutting. Growing them from seeds is best done using the ‘Takeaway Tek’ method; this literally means germinating them in a plastic takeaway box. The box is punctured to allow airflow, and the seeds are placed in a moisturized soil/perlite/Moler clay mix in the box. The whole thing is then placed in a zip-lock bag and kept on a surface that receives shade and mild sunlight. After about one year, the baby cacti are ready to be transplanted and start growing.
Growing San Pedro from a cutting (cloning it) is also straightforward. A foot-long cutting is exposed to the direct sun until the cut “heals”, but the remainder of the stem needs to be covered to protect it from the sun. Once the cut is completely dried, the cutting is potted in a mix of perlite and sand or some type of easily drainable soil. It is placed in a shady and dry place and isn’t watered for a couple of weeks or months until the roots develop. After that, it can be placed in the sun and watered every few days after the soil dries from the previous watering.
The San Pedro cactus is unstoppable; it can grow at a substantial rate—about 30 cm (12 inches) per year, and is highly resistant to pests and diseases, aside from potential fungal infections as a result of overwatering. If a column has been cut or broken, one to three new columns normally sprout out from it. Stems can even start growing from a column laid horizontally on the soil; this happens when they are broken due to wind in the wild.
Likely one of the oldest psychedelics known to man, the San Pedro cactus rivals peyote in its ancientness. Archeological discoveries of San Pedro skin rolls in Peru indicate that it may have been used to (at the very least) roll cigars since as early as 2,200 BC. Additional evidence has been found of San Pedro sacramental use by the Cupisnique (1,500 BC), Chavín (1,000 BC), Salinar (400-200 BC), Nazca (100 BC-AD 700), Moche (100-750 AD), and Lambayeque (750-1,350 AD) cultures.
The artifacts found include ceramic engravings, textiles, and temple stone carvings. The most famous remnant is a carved stone-tablet depiction of an avian fanged serpent god holding a ‘‘staff’’ of San Pedro cactus discovered in an old temple at Chavín de Huantar in the northern highlands of Peru, which dates back to about 1,300 BC.
San Pedro was used in these civilizations by shamans as a means of connecting with the ancestors and communing with deities for the good of the community, most notably on matters concerning water supply and crop growth.
Water has, since the beginning of these ancient Andean civilizations, represented a core aspect of political power and, later on, mythology. In the dry coastal plains and highlands of Northern Peru, which is considered one of the epicenters of San Pedro use, manipulation of water was crucial for the survival of the population. Leaders’ claims to power were equated to the efficiency of the complex aqueducts and irrigation systems built to control the water supply.
In the Moche civilization’s ceramic artifacts, the use of San Pedro appears to facilitate “abundant water and agricultural fertility achieved through communion with the realm of the dead and the ancestors achieved through blood sacrifice.’’ In their depictions of San Pedro, we can see early indications of it symbolizing water and, hence, power.
Throughout the 5th and 6th centuries, as the Wari (Huari) empire expanded toward the highlands (likely prompted by sustained drought in their coastal region), water was firmly established as the key to life in this powerful culture’s cosmology, and its sources were understood to be sacred sites—rituals of communion with other worlds would be performed there. Water also became the symbolic medium through which this passage between worlds would be performed. One of San Pedro’s colloquial names then becomes self-explanatory: agua collay, or the ‘water queen,’ would guide its takers to the realms of the dead and the gods.
After the arrival of the conquistadors in the 16th century, San Pedro use was, as with other entheogens, declared witchcraft and suppressed, although not as violently, as the use of peyote in Central America. The indigenous people cleverly revised the cactus’ name to San Pedro partly in order to appease the colonizers by integrating Christian symbolism into their lore. The name was aptly chosen, too, as Saint Peter was the holder of the keys to heaven, just as the cactus unlocks the doors to other worlds. San Pedro remained out of sight of Western eyes for the next four centuries until its eventual rediscovery in 1945, when its ritualistic use by Andean Indians in Ecuador was again reported.
A few decades later, probably due to its mescaline contents being significantly lower than those in peyote, San Pedro escaped stringent regulations that outlawed the consumption and cultivation of its smaller globular relative in 1971. Its sacramental use continued to this day in similar ways as it always has been used, and it was additionally promoted to Western soul seekers by subsequent anthropological and ethnobotanical reports.
Traditional ceremonies are performed by shamans on special altars (mesas) erected in sacred sites for healing and treating enchantment and bad luck. The mesa rituals involve insufflation of a tobacco and alcohol mixture, ingestion of San Pedro, diagnosis of the patient’s affliction, and cleansing of the evil energies; this is all done by the shaman. Little distinction is made between the mind and body in terms of the illness; the healers look into the spiritual causes even when only somatic symptoms are observed. These ceremonies are held in the early hours of Tuesdays and Fridays, sacred days in Andean cosmology.
Numerous objects of power would be arranged on the mesas; their purpose being to embody the vital force which unites humans with the Earth and the cosmos. Their power is invoked by the shaman for the purpose of healing. When not in use, the power returns along an umbilical cord-like filament to its place of origin, such as a spiritually charged cave, a spring, a mountain, a highland lagoon, or other magical natural site.
At times, more complex potions are prepared using other plant teacher ingredients such as tobacco, coca leaves, Brugmansia flower petals, vilca (Anadenanthera colubrina, one of the most potent hallucinogens in existence), and, occasionally, powdered bones or cemetery dust. This brew is called cimora, and it’s always served at midnight after ritualistic elements such as prayer, tobacco smudging, chanting, and rhythmical rattling have been performed. All those present at the ceremony partake of this potent potion.
Contemporary San Pedro ceremonies are held during the day or nighttime, in a maloca (ceremonial hut) or outdoors in nature. They are abundant and easy to find in Ecuador and Peru; most retreat centers serving ayahuasca also have San Pedro available, either as an add-on ceremony or as its own rite. Add-on ceremonies are usually held on the day following an ayahuasca session, and retreat centers often describe them as providing the participant with the power to enact the changes that ayahuasca showed them are needed.
The main psychoactive ingredient in San Pedro is mescaline. Its content is highly variable—depending on the cactus’ age, location, season of harvest, and how much environmental stress it was exposed to, the concentration of mescaline will be between 0.006% and 0.14% in fresh cacti and between 0.1% and 2.375% in dried cacti; considerably lower than in peyote. The highest levels are found in the 1 cm layer of green flesh just beneath the skin. The whiter layers beneath contain little to no active alkaloids.
Unlike other naturally occurring entheogenic compounds such as psilocybin and DMT, mescaline is a phenethylamine, more similar to chemically synthesized substances such as MDMA and 2C-B. This chemical difference seems to be reflected in the San Pedro experience, which is more commonly characterized by powerful emotional release than by visual hallucinations (although they are present).
Mescaline binds non-selectively to most serotonin receptors in the brain, with primary affinities for 5-HT1A, 5-HT2A, and 5-HT2C. Like with many other classical psychedelics, its main mechanism of action is thought to rely on the activation of the 5-HT2A receptor.
Also like most psychedelics, mescaline does not create a physiological addiction, and it has been found to not cause any psychological or cognitive defects in users. However, as a serotonergic system activator, it does build a tolerance that occurs due to receptor recovery. This means that consuming it on consecutive days will lead to a diminished effect. Additionally, it causes cross-tolerance with other serotonin-based psychedelics, such as LSD and psilocybin. Several days are needed after consumption for the receptors to return to baseline levels of functioning.
Can San Pedro Be Detected in a Drug Test?
Mescaline can be detected in the urine for 2-3 days, in the blood for up to 24 hours, in saliva for up to 10 days, and in a hair follicle drug test for up to 90 days. Most standard drug tests do not screen specifically for mescaline, but it may show up as an amphetamine as they are structurally very similar compounds.
Aside from mescaline, the San Pedro cactus contains a number of other alkaloids in smaller or trace concentrations. These include anhalonidine, anhalinine, hordenine, tyramine, 3,4-dimethoxyphenethylamine, 4-hydroxy-3-methoxyphenethylamine, 3-hydroxy-4,5-dimethoxyphenethylamine, 4-hydroxy-3,5-dimethoxyphenethylamine, and 3-methoxytyramine. The variety of compounds found in San Pedro is significantly smaller than that of peyote, which houses over 50 alkaloids aside from mescaline.
There is not so much information available about the effects of these other alkaloids, except for hordenine and tyramine. Hordenine (or anhaline) is known to raise blood pressure, expand the respiratory system, and constrict the vascular system. It also has adrenergic effects and antimicrobial properties. Tyramine is a naturally occurring alkaloid found in many foods and drinks, notably, anything dried, aged, preserved, pickled, cured, smoked, or fermented, in some nuts, beans and legumes, fruits, and chocolate. It also raises blood pressure and is metabolized in the stomach by monoamine oxidase (MAO) enzymes.
There are numerous ways to prepare San Pedro for consumption. The cactus can be ingested fresh, dried, pulverized, brewed in a tea, or reduced and strained, yielding a sludge high in mescaline content.
Whichever method is selected, the cactus first needs to be prepared. This is done by removing the thin outer skin and spines. The cactus is then cut either vertically along the ridges or horizontally into star-shaped “coins”. The innermost wooden white core is removed, and what’s left is consumable.
The flesh can be cut into smaller pieces and either consumed fresh or after drying in the sun; the latter decreases chances of nausea. The pieces can further be blended with an equal volume of water and consumed as a smoothie, or slowly simmered on low heat, adding more water as the liquid reduces. The latter method takes from 3 to 12h hours to yield a thick sludge, which can then be strained, with the resulting liquid being a potent alkaloid-rich extract. It can be combined with juice for a better taste.
Finally, crystal mescaline can also be extracted chemically from San Pedro by following this method. However, a pure mescaline experience is markedly not as full-bodied as an actual San Pedro trip because the remaining alkaloids are not present.
Due to the wide range of mescaline levels (the highest concentration measured is 20 times stronger than the lowest), it is especially difficult to discuss dosages of San Pedro. It’s impossible to accurately determine the concentration of a stem, as this depends on too many variables.
Here are the mescaline dosages recommended for different trip levels:
Threshold |
100 - 150mg |
Light |
150 - 250mg |
Moderate |
250 - 350mg |
Strong |
350 – 500mg |
Extreme |
>500mg |
The typically recommended “moderate trip” dose of mescaline should be contained in about 200 - 300g or 20 - 30 cm of the fresh stem, providing its mescaline concentration is around the normal 0.1%. However, although rare, that weight can contain a dangerous amount of the substance. This is why it’s best to follow the indigenous tradition and consume little by little in intervals of over an hour, as per need.
The San Pedro trip is not quick to come on, taking up to 45 min to show first effects and up to 3 hours to peak. It generally lasts longer than a peyote trip, up to 14 hours, but is typically not as intense.
The Huachuma experience is often characterized as an emotionally opening journey that keeps the user relaxed, lucid, and in control of both the mental processes and motor functions. The come-up is usually felt as light dizziness or drowsiness, with a tingling sensation in the extremities. Nausea and vomiting are normal occurrences but not as common as with ayahuasca. Due to this, it’s advised to fast for up to 12h before consuming San Pedro.
The peak of the trip is commonly accompanied by strong enthusiasm and feelings of comfort and joy. Visualizations usually include enhanced colors and lights, as well as kaleidoscopic and fractal displays behind closed eyes. They are normally not as complex as peyote. Synesthesia (cross-modal perception) is possible with San Pedro, as well as out-of-body experiences. In typical mescaline fashion, the dimensions of everything in the environment are distorted and undulating, while objects emit auras of mysticism and otherworldly beauty.
Throughout the trip, heightened emotional and spiritual awareness allows profound insight and release to happen. Replays of past events are common to experience, as is the realization of dysfunctional patterns of thought and action as a result of empathy toward the self. To maximize these potential spiritual benefits, it is worth it to prepare for the experience by considering your intentions behind it. Additional affirmations of intentions are usually made at the beginning of the trip so that they can be held onto during the journey. Bad trips can happen with San Pedro, but they are uncommon and most often the result of poor setting and mindset.
The comedown is typically slow and gentle, lasting many hours and leading into an equally long, mellow afterglow.
These two species are the best-known psychedelic cacti, and the choice between San Pedro or peyote is a common dilemma for mescaline-curious psychonauts. Although they both contain this compound, their concentration in each differs. Because San Pedro usually doesn’t contain as much mescaline as peyote does, more of the cactus flesh is ingested to compensate. Still, the alkaloids in San Pedro are not as numerous as those in peyote, making the two experiences quite distinct.
Practically, the trips differ in the following ways: the San Pedro experience is sedating and dreamy, while the peyote one is stimulating and vibrant. San Pedro is often taken during the day, as the visions aren’t too intense, and the whole experience is unobtrusive enough to allow for physical movement. On the other hand, peyote is best communed with during the night as the stronger visuals are easier to see then, and it sometimes renders the user completely unable to move.
Overall, peyote trips are generally considered more powerful and profound. On the other hand, its ecological constraints steer most of those interested in mescaline toward the more abundant San Pedro. The lighter nature of the San Pedro trip is also more suitable for those who don’t have much experience with strong psychedelics.
Although there aren’t many studies into the therapeutic powers of San Pedro, it’s no coincidence that this cactus has been used for its medicinal properties since ancient times.
Anecdotal records of shamans healing a wide variety of psychological and somatic plights with San Pedro are abundant. Whether it’s consumed by them to diagnose the illness or by their patients to purge toxins or receive spiritual insights, San Pedro has been a vital ally of indigenous communities for thousands of years. Over the last few decades, Westerners in need of healing and personal growth could commune with Huachuma, too.
Issues San Pedro can purportedly help treat include pain and inflammation, infection, paralysis, blindness, mood disorders, grief, depression, substance and alcohol addiction, and others. There is some evidence regarding the effectiveness of mescaline as a therapeutic substance, but more scientific research is needed to verify and ascertain San Pedro’s medicinal benefits.
Mescaline is a serotonergic system activator, and it may interact negatively with other chemicals which change serotonin levels. Additionally, San Pedro contains tyramine, an alkaloid that can interact negatively with MAO inhibitors such as some depression medications; these should be discontinued for a few weeks before ingesting San Pedro, or there is a risk of developing the potentially fatal serotonin syndrome. Mescaline has also been shown to induce temporary psychopathology and can trigger psychopathy in individuals with a predisposition to it.
Due to the presence of hordenine, which raises blood pressure, San Pedro is also not safe for individuals with pre-existing cardiovascular issues. Finally, as it also affects the adrenergic system, no other stimulant substances should be used concurrently with San Pedro.
It’s best to stay off of any chronic medication or intoxicating substances if planning a San Pedro trip, as the interactions are not well known to science. As therapeutic as this cactus may be in terms of helping with substance addiction, it should not be combined with them.
Contrary to peyote’s legal status, and likely due to lower levels of mescaline, cultivating San Pedro as a cactus species is perfectly legal in most of the world. The only caveat is that it’s legal only for ornamental purposes; its use as a psychedelic and possession for purposes of extracting mescaline is illegal. This doesn’t apply to its native countries—Ecuador, Peru, and Bolivia—where sacramental use is allowed.
