What Is Huachuma or San Pedro cactus? Experience, Benefits & Side Effects

Therapist, shamanic practitioner, retreat & workshop leader, ceremonialist and speaker.

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Because it is a bit gentler than many of the other plant teachers, Huachuma has earned the nickname “The Grandfather” around the medicine community. Make no mistake though, San Pedro can produce as deep visions as any other entheogenic, Ayahuasca, Buffo Alvarius or Psilocybin mushrooms. However it is overall less intimidating, less jarring and more loving than many other plant teachers. His main personality is two-fold: heart-opener, and nature reconnection. He will also show you the foundation of the cosmos and what holds the universe.

What is San Pedro cactus or Huachuma?

Huachuma — also known as the San Pedro cactus — is a brew made from a variety of cacti mostly found in the Peruvian and Andeans highlands. The three most commonly used cacti are Trichocereus Pachanoi, or the Peruvian and Bolivian torch, respectively Echinopsis peruviana and Echinopsis lageniformis. A thick layer of the skin is used in the preparation, though other plants or ingredients can be added as well.
This drink has been used for healing, spiritual and religious purposes by ancient cultures in the northern part of South America for over 5700 years(1) and is still used in sacred drinking ceremonies by many spiritual communities in this part of the world.
Traditionally, a shaman also called curandero or a laika — an experienced medicine man or woman who leads San Pedro ceremonies — prepares the brew by boiling the skin and parts of the flesh of the cactus in water over long periods of time. The brew or medicine is then shared in ceremonial circles, mostly during day-long ceremonies. Less commonly it can also be served at night.

The San Pedro cactus is peeled and cut before being boiled. Interestingly, during the preparation the shaman uses constant prayers and shamanic rituals. They are just as important, if not more, than the 12-20 hours boiling process to extract it’s medicinal compounds. The preparation is itself a sacred ceremony.
The brew reduced to the right thickness and spiritual potency is then cooled to be shared in healing ceremonial gatherings.

Because it is a bit gentler than many of the other plant teachers, San Pedro has earned the nickname “The Grandfather” around the medicine community. Mescaline itself is nontoxic and non-addictive. And, while there are few studies done on San Pedro itself, a Harvard Medical School study that investigated the long-term effects of regular peyote use among members of the Native American Church found “no evidence of psychological or cognitive deficits”.
Make no mistake though, San Pedro can produce as deep visions as any other entheogenic, Ayahuasca, Buffo Alvarius or Psilocybin mushrooms. However it is overall less scary, less jarring and more loving than many other plant teachers.

How does it work? San Pedro’s 4 pillars

As mentioned above, the consumption of the cactus is done natively in spiritual ceremony, a special ritual gathering with a specific intention, usually therapeutic or spiritual. The four pillars or main components of a San Pedro ceremony are the plant itself, the ceremony, the shaman or facilitator and the intention.
Each component is crucial to the outcome as they each contribute a specific and vital aspect in the revelation of the Plant’s Spirit, it’s personality, it’s messages and its healing powers. When successfully combined, these four components form the essential tapestry of the shamanic world, more recently paralleled to the quantum approach to reality that modern science is only starting to unravel.

Discarding only one of the four components, for example, consuming the plant by itself in ceremony but without intention, or with intention but without guidance, will usually result in milder effects, possible confusion, visions without meaning, and the integration of the process may be rendered difficult, if it ever happens. Somehow, an ‘incomplete’ ceremony may miss the full scope and range of this powerful process.

N.B: The scientific approach to understanding the world —based on measurement, repeatability and falsification as its sole operating principles and goals— must also, by definition, discount the ceremonial, shamanic, spiritual and psychic (emotional, individual and psychological) experience of anyone partaking in a San Pedro ceremony. In fact, a spiritual or personal experience cannot be effectively measured as it is subjective and anecdotal only. Consequently, what scientists really measure, is a notion of “what is really happening” at a structural or chemical level. From a scientific perspective, the reality of the experience for millions of people who have used ancestral plants for spiritual, emotional, or physical healing for thousands of years must be fatally ignored.

The plant

The main psychoactive component of San Pedro is mescaline. However, as well as its mescaline content, San Pedro contains a range of compounds that have effects of their own. By focusing only on mescaline, adepts and scientists may tend to miss or devalue their contribution to the experience as a whole. Some of these compounds are sympathomimetics, or substances that mimic the effects of adrenalin and noradrenaline, the so-called fight or flight chemicals that are released naturally by our bodies when we feel uncertain or anxious. These additional compounds combined with mescaline may also contribute greatly to the sense of awe and awareness that you are in the presence of something mysterious and greater than ourselves, which are common feelings under the influence of San Pedro. The assumption made by the scientific approach that mescaline is the sole active compound of San Pedro may well be one a leading error—although it is all too common in plant medicine research.

The Shaman or facilitator

The Shaman is a trained individual, medicine man or woman, either indigenous and native or a person with a more western understanding of shamanic perspectives. The shamanic realm is intricate and it’s knowledge requires the ability to navigate different realities. More specifically in a San Pedro ceremony, the sham or facilitator will create and sustain a particular space propitious to the safe unfolding of a ceremony. She will also loo after each individual and support them when help is required. The tools of an authentic and developed shaman are varied and the presence of an experienced facilitator is invaluable for participants to make the most of a unique process.

The Ceremony

Each ceremony follows a very specific orchestration of the day-long process. It is led by the shaman. The use of different ancestral medicine wheels [structured shamanic cosmovisions specific to different lineages, traditions or origins] is common in San Pedro ceremonies. For a day-long San Pedro experience the ceremony is the container, the rituals within that container can vary greatly depending on the shaman and their own tradition. A ceremony offers a framework easily and safely accessible by participants; it contributes and deepens the experience through the use of sound, music and various shamanic healing skills processes offered by the shaman. Interestingly, some shamans may also decide to ignore any traditional framework and let the person be with the experience for hours on end. Their presence, the quality of their holding space and their personal intention are however the glue that makes the experience viable.

The Intention

Like all other great teaching plants of Peru, San Pedro is always taken as part of a shamanic ceremony with the intention of healing—never lightly and never as a “recreational drug.” Healing in a ceremony like this is defined more broadly than a Western doctor might understand the term, and means an ultimately beneficial or positive change in the mental, emotional, or spiritual aspects of one’s life as well, often, as a physical cure or change.

The energy of intent is a very powerful force, and all healers must master it because the plants respond to it in their own language.

Correspondingly as important is the participant’s intention. In the process of achieving the desired goal and to enlist the help of a Plant spirit as well as to invite the teachings to come forth, the participant has a crucial role to play. In all traditional ceremonies and even more so in modern gatherings, a participant will be asked to prepare, in stillness, an intention to bring to the process. During the ceremony, she will also be invited to ritually share her intention into the fire. Intention is one of the most important keys to achieving success on this highly transformative path.

How is San Pedro used?

Though San Pedro was traditionally used for spiritual purposes by specific tribes, it has become popular worldwide among those who seek a way to open their minds, heal from past traumas, experience deeply the divine and a connection to nature, or simply experience a San Pedro journey.

It’s highly recommended that San Pedro only be taken when supervised by an experienced facilitator or shaman, as those who take it need to be looked after carefully, as a San Pedro experience leads to an altered state of consciousness that lasts for many hours.

Many people travel to countries like Peru, Colombia or Ecuador where multi-day San Pedro retreats are offered. They’re led by experienced facilitators, who prepare the brew and monitor participants for safety.

Before partaking in a San Pedro ceremony, it’s often suggested that participants follow a regimen diet of light, mostly vegetarian meals, at least one-week prior to the experience and abstain from drugs, alcohol and sex. This is recommended in order to cleanse the body of toxins and maximise the effects of the experience.

The ceremony

San Pedro ceremonies are commonly held during the day although night ceremonies are also offered. They seem to each offer a different quality to the work with the plant. After the space is prepared and sacralised with shamanic rituals by the shaman of facilitator leading the ceremony, San Pedro is offered to participants, sometimes split into several doses.

After ingesting San Pedro, most people will start to feel its effects within 1-2 hours, sometimes a lot faster. The effects are dose-dependent, and the journey can last 8–12 hours

Those who take San Pedro can experience symptoms like nausea, vomiting, diarrhoea, various human feelings at various depths, strong visions, mind-altering psychedelic effects, and extremely rarely fear.

It should be noted that some of the adverse effects, such as vomiting and diarrhoea, are considered a normal part of the cleansing experience.

People react to San Pedro differently. Some experience euphoria and a feeling of enlightenment, while others go through an increase of anxiety and panic. It’s not uncommon for those taking San Pedro to experience both positive and negative effects from the brew.

The shamans or facilitators who are experienced in San Pedro offer help and guidance to participants throughout the San Pedro experience and monitor participants for safety.

These ceremonies are sometimes conducted consecutively, with participants consuming San Pedro a few consecutive alternative days or mixed with a night ceremony. Every time you take San Pedro, it results in a different experience.

Summary San Pedro ceremonies are typically led by experienced shamans or facilitators. San Pedro takes between 20 minutes up to 2 hours to kick in, and its effects can last up to 12-14 hours. Typical effects may include strong visions, deep feelings, euphoria and vomiting.

Working with San Pedro

Diet preparation

All teacher plants require some ritual preparations. It not only refers to eating or drinking moderations but also to other behaviours so the participant enters a ceremony with a clearer frame of mind and a pure intention as well as a cleansed body.

The cactus San Pedro does not ask for changes as stringent as for other teaching plants but, nevertheless, food prior to the day of ceremony should be bland and contain no alcohol, meat, oils or fats, spices, citrus fruits, or juices and there should be no sex. No food for about twelve hours before the ceremony, means a day of fasting if you are drinking San Pedro at night, or no food from about 8 p.m. on the night before if you are drinking it the next day. A few hours before the ritual you are invited to enter a period of quiet reflection so you can prepare your intention, what you want to heal in your life or learn about yourself. There are also some specific conditions where a consultation with your facilitator and medical doctor is recommended in advance of drinking San Pedro. These include conditions with the colon, high blood pressure, heart conditions, diabetes, or mental illness. None of these will necessarily prevent you from drinking since the condition itself may be the very thing that you want San Pedro to cure, but your shaman and doctor must be made aware.

The experience itself

After drinking San Pedro, the time it takes to start feeling the effects varies greatly. Some people will start feeling the effects within0 5 minutes, and for others it may take up to 2 hours. When it starts it’s usually gradual and will peak at around 4 hours after ingestion. Be open to a longer ride than with others entheogens as the ride may last 8 to 14 hours. When drinking San Pedro in ceremonial space, each step of the ceremony will invite different phases in the experience. The sounds, chants, icaros [channelled songs] and music are an important component of the process and the shaman or facilitator will usually provide a vocal and musical soundscape to guide you through the realm of spirits.

The induced state of heightened consciousness is as if you’re traveling in different worlds and realities. Very rarely reported are moments where you do not feel completely in control of your movements, your thoughts or your personal will.

San Pedro unlikely many of the plant teachers require a free-will act of surrender, to engage deeply with it. You may feel like you don’t want to move much during a ceremony, and while you can still go to the bathroom, you will not feel as if you want to do so.

Nausea is an expected but not systematic effect and it doesn’t usually last for very long. After the nausea wanes, San Pedro enters and moves through your consciousness. You enter a lucid but dream-like state.

Once the opening of your physical body to non-ordinary states of awareness happens, you will be introduced to a whole new dimension that you’ve never experienced before. Visions, feelings, a symbolic language and direct knowings are very familiar to the San Pedro language. You may also be introduced to your spiritual guides, and they will connect you through to the endless inner depths of direct knowing. The brain or mental activity is bypassed, or dulled to the benefit of another way of knowing. These are the hallmarks of the San Pedro journey.

Some have reported feeling extreme sadness, aversion throughout entire journeys, while others may experience nothing but bliss and joy. It depends on your psychological state, the intention you brought to the journey and the parts of you that need healing. The more opened or attuned you are to your experience as a whole, the more positive your experience will be.

As the non-ordinary awareness grows, you feel like your soul is voyaging beyond your body. As worldly objects glow with ethereal colour, you perceive a significant underlying energy to all things, and the world and yourself in it seem to click together in one huge, expansive understanding.

The above is typical of an experience with San Pedro. While San Pedro has been used by indigenous cultures of South America for thousands of years — making it the oldest recorded entheogenic medicine — it hasn’t enjoyed the popularity of the more famed master plant like Ayahuasca or psychedelics like LSD and psilocybin mushrooms. However, those who have experienced this powerful plant agree that it is strong medicine for whatever ails you.

When it wears off

When the effect wears off, your ordinary physical senses start to come back to you. And you can rest knowing that you have connected your mind with the spirits. Modern integration processes are usually offered to various degrees with the most elaborate ones being bridged by western-trained shaman or facilitators. These integration processes are usually offered the day after a ceremony.

Potential benefits of San Pedro

Many people who have taken San Pedro claim that the experience led to positive, long-term, life-altering changes.

Recent research has shown that San Pedro may benefit health — particularly brain, gut, immune and neurologic health — in a number of ways.

Overall health related questions

The main active ingredients in San Pedro — Mescaline and other sympathomimetics compounds mimicking the effects of adrenaline and noradrenaline — have been shown to exhibit neuro-protective and neuro-restorative qualities in some studies. San Pedro is also highly alkaline and as such offers the benefits of boosting immunity, neutralising the acidity in your body caused by poor diet, stress or environmental toxins.

Various patients have claimed that this physical healing can include relief from such disparate conditions as diabetes, hepatitis, cancer, paralysis, joint problems, fever, high blood pressure, cardiac disease, and burning in the kidneys and bladder. San Pedro is also said to be an antimicrobial agent that can inhibit at least 18 different kinds of penicillin-resistant bacteria.

May improve psychological well-being

In our world, there are literally millions of people stuck in behavioural, cognitive, emotional patterns that no longer serve their wellbeing, connection and relationships. We all grow accustomed to these and when they fail us we develop coping mechanisms. A vast proportion of humanity is however willing to grow, change, transform these deeply limited behaviours and patterns so they can feel free from their burden. Through the use of all entheogenic medicine and in this case of the plant teacher San Pedro, one can gain the personal empowerment needed to take charge of life and move beyond our own negative influences or limitations.

Following a San Pedro ceremony, negative patterns in one’s life will often come to light: old habits, bad habits, bad company, bad environment, a tendency to linger unhappily in a bad relationship, a desire to repair a relationship without knowing how, the inability to say ‘no’, etc. This is a process opening people to not only deeper wisdom, but also a certain inner spiritual strength to accept and acknowledge the negative things that exist in their lives and to let them go or, to eradicate those limitations from their lives.

However, in the absence of careful planning and good guidance, San Pedro can be anti-productive. Absence of respect — if one treats it as a drug, for example, or takes it too frequently and in unwise circumstances — then a shift can occur in the way the plant works with the individual. Or if one fails to follow the guidance and lets the energy build up or bottle up, it may also engender disturbances or frustration that can be very unnerving or unsettling to some people.

Working with Sacred plants can also be a difficult path paved with hurdles and tests. The plant seems to specifically go to your very weaknesses. The whole point of the experience is to help you strengthen your weaknesses and grow from that point on. What this results in is an unmatched fast pace of personal development and evolution of consciousness. That process is enhanced as much by how you do it, where you do it, and why you do it as by the plant itself.

Most of the deep healing work usually occurs in the days, weeks or months following the ceremony. During this integrative period, one simply digests the flow of life at a deeper level. You begin to refine the composition of your own life in a wiser, more responsible way. This manifests in noticeable changes in the way people treat themselves and those around them. It is a transformation that brings about deep and long-lasting changes, not reduced to whilst under the influence of the plant in ceremony. Most people will never quite be the same after this experience.

Research has shown that taking San Pedro may increase mindfulness capacity of your brain and improve your overall psychological well-being.

A study in 20 people indicated that consuming San Pedro either in intensive retreats or on a regular basis, once weekly for 4 weeks was as effective as an 8-week mindfulness program at increasing acceptance — a component of mindfulness that plays a fundamental role in psychological health — and resilience.

Other studies have found similar results, noting that San Pedro may improve mindfulness, mood, and emotional regulation.

A study in 57 people demonstrated that ratings of depression and stress were significantly decreased immediately after the participants consumed San Pedro. These effects were still significant 4 weeks following the San Pedro consumption.

The experience of the author of this article attests of long-lasting therapeutic changes in a variety of conditions as depression, diabetes, sleep disorders, chronic pain, migraines, and immune related disorders.

May help treat addiction, anxiety, treatment-resistant depression, and PTSD

Advocates of this medicine also frequently cite its ability to cure drug addiction and alcoholism. San Pedro reveals the underlying causes of these addictions by bringing elements of the subconscious mind to the attention of the conscious mind. This can include life events participants haven’t thought about in years, in some cases early childhood memories— often things that have had a profound influence on their adult lives without their being aware of it. In discovering or unraveling these unresolved issues, one can find closure and integration.

Some research suggests that San Pedro may benefit those with depression, post-traumatic stress disorder (PTSD), and addiction disorders.

A study in 29 people with treatment-resistant depression showed that a single dose of San Pedro led to significant improvements in depression severity compared with a placebo. Other studies report rapid antidepressant effects of San Pedro as well.

Additionally, a review of six studies concluded that San Pedro showed beneficial effects in treating depression, anxiety, mood disorders, and drug dependence.

Several studies have focused on the effects of San Pedro on addiction disorders, including addictions to crack cocaine, alcohol, and nicotine — with promising results.

In one study, 12 people with severe psychological and behavioural issues related to substance abuse participated in a 4-day treatment program that included 2 San Pedro ceremonies. At a 6-month follow up, they demonstrated significant improvements in mindfulness, hopefulness, empowerment, and overall quality of life. Plus, self-reported use of tobacco, cocaine, and alcohol significantly declined .

Researchers hypothesise that San Pedro may help those with PTSD as well, though more research in this area is needed .

Summary According to current research, San Pedro may protect brain cells and stimulate neural cell growth and improve some severe known conditions. It may also boost mood, improve mindfulness, and treat depression and addiction disorders, though more research is needed to confirm these effects.

Considerations and potential side effects


Toxicity to San Pedro has not been studied enough to determine what quantities could be dangerous to ingest. However, thousands of years of shamanic use and no reported complication or even deaths linked to San Pedro speaks volumes.

Considering the human dose of mescaline is around 200-500mg orally means a fatal dose would be extremely difficult to ingest and very unlikely to happen accidentally.

Users experience very different sensory and perceptual experiences, such as time passing more slowly, colours appearing brighter, sounds seeming sharper, or even “seeing” sounds and “hearing” colors. Some users experience strong visions, or feeling a sense of almost tangible connectedness to objects and the world around them. They may feel weightless or extremely heavy to the point of immobility, or anything in between.

While taking part in an San Pedro ceremony is far from a well-documented process, consuming this entheogenic brew has never been documented to lead to any serious side effects.

Even though some side effects often experienced during a San Pedro trip, such as vomiting or diarrhoea, paranoia can be unpleasant they are considered normal and only temporary and do not occur with lasting impact.

Tolerance, Dependence, and Withdrawal

There is no current research suggesting that mescaline use leads to physical dependence, psychological dependence, or addiction. Tolerance means that participants need to take more of the brew in order to achieve the same effects. Structured ceremonies invites participants to learn how to use less of the brew to obtain the same if not wider results.

How Long Does Mescaline Stay in Your System?

The amount of time mescaline stays in the system depends on factors such as an individual’s metabolism, hydration levels, body mass, and overall health. Mescaline can be detected in urine for between two to three days after ingestion but can be detected by hair follicle tests for up to 60 days.


Mescaline does not appear to be addictive or habit-forming, although further research is needed to determine if addiction is possible. That said, any substance that affects up the user’s mundane perception of reality comes with potential issues, as users can more easily misinterpret reality. In terms of toxicity, however, evidence may point to mescaline carrying a lower risk than many other recreational drugs.

There is no current research suggesting that mescaline use leads to physical dependence, psychological dependence, or addiction. Tolerance means that people need to take more of the drug in order to achieve the same effects.

Overall, there have been promising findings related to the health benefits of San Pedro, however, more research is still needed to determine the array of potential treatments for certain medical conditions in the future.

Summary Based on existing research, taking San Pedro has very little or no serious reported side effects. Interaction with any existing medication is unreported. Various serious medical conditions  such as diabetes, immune system related conditions, depression and heart conditions have been shown to improve considerably. San Pedro is thought to be one of the safest entheogenic or psychoactive plants in existence.

The bottom line

San Pedro is prepared from parts of the Trichocereus or Echinoi cactus gender.

It has powerful entheogenic properties and may cause positive health and wellbeing effects.

More research is certainly needed to determine whether it can be used as a safe alternative treatment for certain health conditions.

If you’re interested in participating in an San Pedro experience, be sure to do your research and know that safety is reasonable however not guaranteed — the way to minimise risks and maximise the potential benefits is to work with experienced shaman or facilitators.