About San Pedro

Huachuma is more commonly known as San Pedro in the Western world, its scientific name is Echinopsis pachanoi.

San Pedro in flower at Rustlers Valley South Africa 2007

Huachuma is a tall, light green, night-blooming, nearly spineless, columnar cactus native to the Andes Mountains. In its native habitat, it grows at altitudes of 6,600 – 9,800 feet. This cactus is found in parts of Columbia, Ecuador, Peru, Bolivia, Chile, and Argentina, but is also cultivated in neighboring countries and many other parts of the world. It is considered the most ancient and revered plant teacher amongst the curanderos of northern Peru.

The fact that San Pedro grows vigorously in the wild or cultivated in a home garden makes it a better choice for consumption over its slow-growing and endangered cousin peyote. Like peyote, the San Pedro cactus has a rich history of traditional shamanic use. Despite the two sharing mescaline as their primary active alkaloid, there are substantial differences between the other psychoactive compounds found in each of them. This results in the two having very different characteristics. When ingested, huachuma is usually described as the gentler of the two, but its effects can be felt a little bit longer than that of peyote. The effects of peyote can be felt about 10 to 12 hours while Huachuma can last between 12 to 14 hours or more depending on the dosage.

Uv cactus pic

San Pedro cactus has been used ceremoniously for around 3500 years by indigenous groups in Peru. The earliest known use comes from a stone carving that dates back around 1300BC. It very clearly depicts a huachuma shaman holding a tall San Pedro cactus. The carving was found at the Jaguar temple at Chavín de Huantar in Northern Peru. This carving comes from the Chavín culture.

Effects of San Pedro

Scientific data regarding the use of E. pachanoi (San Pedro) has proved to be quite elusive or is virtually nonexistent. This is a tragedy because this plant has several real medicinal and psychotherapeutic uses. This plant like so many others deserves scientific investigation so that it can be properly integrated into our societies.

The most prominent information about the uses and effects of San Pedro comes from traditional or folk medicine people. Over thousands of years of first-hand experience, Peruvian shamans have developed a way to use San Pedro to diagnose and treat diseases.

The following alkaloids are generally found within E. pachanoi: Mescaline (25 or more mg per 100 grams of fresh cactus), 3,4-Dimethoxyphenethlamine, 3-Hydroxy-4,5-dimethoxyphenethylamine, 3-Methoxytyramine, 4-Hydroxy-3,5dimethoxyphenethtlamine, Anhalonidine, Hordenine, and Tyramine. The concentration of these alkaloids can vary widely for each plant.

Early shamans used San Pedro as a sacrament. They would consume it orally and part of the effects would allow them to be able to see an illness. This, in turn, would allow them to diagnose their patients. Identifying the illness has always been essential to finding a cure or proper treatment to begin the healing process.

Sometimes the patient would also take San Pedro with the shaman. The patient underwent a purification ritual that involves consuming a tobacco extract that was suspended in alcohol through their nose using a snail shell. This is believed to protect them from harmful powers.

This practice is not common today; however, the nicotine-containing plants are still oftentimes used in modern San Pedro ceremonies. Currently, in Peru, both the shaman and the patient ingest the San Pedro elixir after fasting for 24 hours. Today the shaman and patient might be accompanied by others as support. These other people are not necessarily shamans or patients but they drink the elixir to strengthen the ritual.

These San Pedro rituals typically take place at night time. Usually, in front of a mesa (an altar), that is adorned with sacred objects such as shells, feathers, ceramics, or images of saints that hold significant meaning to the shaman or patient. The shamans also include the use of sacred tools such as incense and musical instruments.

The San Pedro ceremonies remained unadulterated for upwards of a thousand years. It was only after the Spanish conquest that the huachuma cactus took on the name, “San Pedro.” Saint Peter is the Christian saint who is said to hold the keys to Heaven’s gates. The name change was the very beginning of Catholic iconography within Andean culture. The fact that Spanish colonists renamed the huachuma cactus “San Pedro” is a clear indicator that they were aware of the plant’s ability to take one into the sacred realms.

The Experience

Mescaline is the main psychoactive component of the San Pedro cactus, so a San Pedro trip is similar to other mescaline trips – like peyote. The experience lasts around 8-14 hours in total and is often described as being very physically stimulating. A San Pedro trip can be very much centered in the body, rather than the mind – a euphoric warm glow moves through the body, which can sometimes alternate to an unpleasant electric tingling or waves of nausea.

Otherwise, the cognitive experience can be similar to other natural psychedelics like ayahuasca and magic mushrooms – deeply introspective, sometimes challenging, and intense.

Holding a San Pedro ceremony for yourself or a loved one is becoming a common practice around the world. There is definitely a traditional way of using the cactus but other modalities that focus on respect and healing also work. The key with this and all other entheogens is respect. A healthy respect for the plant teacher goes a long way. Growing your own San Pedro and using San Pedro that you’ve grown and harvested yourself will provide an unforgettable experience. If you are called to San Pedro and want an authentic San Pedro journey you can book San Pedro Journeys in several parts of Peru. Hopefully one day we will have retreat centers or healing centers in the states that offer San Pedro and other sacred plant medicines.


Toxicity to mescaline has not been studied enough to determine what quantities could be dangerous to eat. However, Thousands of years of shamanic use and no reported deaths linked to San Pedro speaks volumes.

San Pedro is not as demanding as ayahuasca. There is no week-long dieta to follow. Just a few recommendations for the day or days before a ceremony such as cutting out fatty foods, meats, and drugs or alcohol.

San Pedro is one of the safest psychoactive plants in existence. It has many healing benefits as discussed above, however, when traveling abroad the brew can become dangerous if it is brewed with additives by an inexperienced San Pedro enthusiast. Ratsch/ Hoffman noted some traditional additives like toé or angels trumpet (datura) can be fatal if used in excess. It is recommended to avoid ceremonies that involve the use of toé as an additive unless you know for certain that the practicing shaman has years of reputable experience.

Preparing the San Pedro

There are several ways to prepare San Pedro, but the most common is to slice the stalk, and then cut the outer green section into cubes, and boil for several hours until it reduces into a thick dark sludge. Alternatively, the cactus can be dried and ground into powder.

The cut
The fillet
The Gold

See my page on San Pedro preparation here.

Some references:

  1.  The ultimate guide to San Pedro
  2.  History of San Pedro Use and Geographic Location 1
  3.  History of San Pedro Use and Geographic Location 2
  4.  Current Use of San Pedro and Huachumaulture
  5.  Legality Of San Pedro
  6.  Healing with San Pedro (Huachuma)
  7.  Preparation