Written by Alexandra Papanicolaou
The term “San Pedro” is frequently used to refer to the different Echinopsis species, and more specifically the “San Pedro cactus” is referring to the Echinopsis pachanoi. Some of these species, including Echinopsis pachanoi (Britton and Rose) Friedrich and Rowley (E. pachanoi), Echinopsis peruviana (Britton and Rose) Friedrich and Rowley (E. peruviana), and others are commonly used nowdays as a therapy. In particular, indiginous practitioners use these various Echinopsis species for diagnostic and botanical/pharmacological purposes. Such use is evidently based on their psychoactive properties due to their mescaline concentration. Environmental variables, such as temperature and rainfall variations (which are correlated with altitude differences), as well as edaphic circumstances, may play a role in the regional and/or temporal change in mescaline concentration.
E. pachanoi is native to the Andes of South America, occurring at altitudes of around 2000-3000m in southern Ecuador, Peru (where it is locally known as “huachuma”), and Bolivia (where it is known as “achuma”). The base of this cactus typically develops multiple erect branches. It has a cylindrical, dark-green stem with 4 to 6 ribs. E. pachanoi’s spines are frequently small or infrequently absent. When grown as an ornamental hedge plant along field edges, it creates a natural fence. It is a columnar cactus with mature stems that are about 10 cm in diameter and typically grows to a height of 3 to 5 meters . In particular, this cactus has the capacity to grow up to one foot every year when given the correct conditions for moisture, sunlight, and soil. The correct condition for its growing are:
- Soil & Transplanting: It requires fertile, slightly acidic potting soil with sufficient drainage.
- Watering and Feeding: To prevent the development of rot, this cactus should not receive any water from October to April as it enters a dormant state during the winter months.
- Light & Temperature: After the first year, it thrives in full sunlight, and though seedlings may get sunburned. In general, Trichocereus pachanoi thrives under summer heat in mild shade .
Hence, cactus commonly grows on very steep, rocky slopes and cliffs, but because the plant has been domesticated for so long, it is challenging to pinpoint its place of origin and natural environment 
However what is importantly known is that E. pachanoi has the highest mescaline levels (4.7%) in the dried stem chlorenchyma tissue . Mescaline, or 3, 4, 5-trimethoxy-|3-phenethylamine, is generally responsible for the psychoactive action of pachanoid and peruvianoid Echinopsis species. Mecaline sulfate and mecaline hydrochloride are frequently chosen formulations for use in biomedical studies due to their solubility and simplicity of handling. More specifically, due to its low solubility in a cold solution of alcohol and water, mescaline is often extracted from plant materials in the form of mescaline sulfate, which precipitates in pure, crystalline form.
In addition to mescaline, which is the plant’s primary alkaloid, there are also other alkaloids found in the San Pedro cactus including 3, 4-dimethoxyphenethylamine, 3 Methoxytyramine, 4-hydroxy-3,5-dimethoxyphenethylamine, 4-hydroxy-3 methoxyphenethylamine, anhalonidine, anhalinine, hordenine, and tyramine .
The San Pedro is typically cultivated adjacent to homes since it is seen to be a guardian of families, marriage, and harmonious interdependence among family members. Generally, San Pedro is primarily used for diagnostic purposes; the healer consumes San Pedro in order to understand the patient’s illness. Other uses for the San Pedro decoction include cleansing the body because it can cause vomiting and diarrhea when consumed, and as an anti-inflammatory in the form of a topical poultice. However, mescaline must be administered in the right amount for it to be beneficial and safe. The active dose of oral mescaline hydrochloride has a range of 150 to 700 milligrams. Mescaline standard dosages have been derived using aweight based formula of 3.75 mg/kg.
- Threshold dose: 100 mg
- Low dose: 100 – 200 mg
- Average dose: 200 – 300 mg
- High dose: 300 – 500 mg
Besides the good effects of the cactus, people with a history of cardiovascular diseases should avoid using San Pedro due to the possibility of intense experiences that could cause anxiety, especially those who are taking medication to control these pathologies and who have medical conditions for which reduced levels of physical activity have been recommended .
1. Ogunbodede O, McCombs D, Trout K, Daley P, Terry M. New mescaline concentrations from 14 taxa/cultivars of Echinopsis spp. (Cactaceae) (“San Pedro”) and their relevance to shamanic practice. J Ethnopharmacol. 2010;131(2):356-362.
2. Ogunbodede OO. Alkaloid content in relation to ethnobotanical use of 0RW1S34RfeSDcfkexd09rT2trichocereus pachanoi1RW1S34RfeSDcfkexd09rT2 and related taxa. [Order No. 1478388]. Sul Ross State University; 2009.