San Pedro (Wachuma)

San Pedro or Wachuma (Echinopsis pachanoi) grows naturally in the Andean highlands and Mountains, thriving in environments between 2000-3000 metres above sea level. It is a massive cactus that can grow up to a surprising height of 20 feet (six metres) in the wild. San Pedro may display a different number of ribs usually ranging from sets of 4 to 8 ribs, even on the same plant. Its popularity among healers and shamans is mostly due to the large quantity of mescaline contained in the cuticle.

Wachuma cactus has been a central part of healing, spiritual awakenings and religious divination and its employment as a sacrament is thought to have its origins at the dawn of the Andean civilization. Hence San Pedro is believed to be one of the world’s first entheogens to be ingested by humans and evidence of its consumption shows that this tradition dates back at least 3500 years. The medicine men of that time considered it “Materia prima” which is, “a formless primaeval substance regarded as the original material of the universe.” (Ratsch/ Hoffman 505).

The earliest account of its place and importance among a community is from a stone carving which dates around 1300 BC, in the Jaguar temple at Chavín de Huantar in Northern Perú. It clearly depicts a wachuma medicine man holding a tall San Pedro cactus. This sacred cactus is later rendered in artistic and decorative motifs on Peruvian traditional ceramics like the Salinar style of 400-200 BC and the Nazca urns of c. 100 BC-AD 700.

The sacred ceremonial and spiritual use of San Pedro was almost driven to extinction during the colonial oppression. This ancient tradition managed to survive due to the rituals being conducted in secret. Traditional wachuma ceremonies are similar to Ayahuasca ceremonies, both are held in a circle and facilitated by an indigenous shaman. Like ayahuasqueros, wachuma shamans use sound and chanting to direct the ceremony although prominently there seems to be more instruments played at a wachuma ceremony.

Scientific data regarding the use of E. pachanoi (San Pedro) is quite scarce. This is a real mishap because this plant has quite a few real medicinal benefits and psychotherapeutic uses.

A great deal of what is known 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 health conditions. There have been innumerable accounts of “miracle cures” to a wide range of physical and mental conditions which include overcoming addiction, cancer, paralysis, diabetes, emotional and psychological issues such as grief, anxiety, depression, etc.

Toxicity to mescaline has not been studied enough to assess a standard for a dangerous or lethal dosage. However the extended use of San Pedro throughout history and no reported deaths linked to it, indicates that it is one of the safest psychedelics on the planet. San Pedro is not as demanding as Ayahuasca in that there is no real specific diet to follow. Nevertheless It is advised to cut out fatty foods, meats, drugs and alcohol a few days prior to a Wachuma ceremony.


Experiencing a San Pedro journey is similar to other mescaline trips like with peyote. The experience lasts around 8-14 hours in total, and is often described as being very physically stimulating and can come in waves of intense emotions. A San Pedro journey can vary in intensity both in mind and body, it can trigger and amplify powerful mental states and bodily sensations. Usually an euphoric warm glow moves through the body, which can sometimes alternate to heat flushing, waves of energy, electric tingling, or waves of nausea. Otherwise, the cognitive experience may take you to visions, deep introspective moods, sometimes challenging with intense emotions such as immense joy or sadness.

“Considering the human dose of mescaline is around 200-500mg orally, this means you would have to try very hard to take a fatal dose. It would be extremely unlikely to happen accidentally.” (Ross Heaven).

A dose of 50g of dried cactus can contain anything from 150mg to 1.2g of mescaline, ranging from a threshold dose to a potential overdose. A threshold dose of mescaline is about 100-150mg, but this quantity of mescaline could be present in anything from 5-50g of dried cactus. Therefore, you should start by microdosing with as much as 10g of dried cactus, and increase gradually as you progress toward a more intense experience. This is usually advisable because the concentration of alkaloids can vary widely for each plant and is never the same.