San Pedro is a natural medicine derived from the mescaline-containing cactus, Echinopsis pachanoi, which is native to the Andes Mountains of South America. It has been used for thousands of years by indigenous peoples for spiritual and medicinal purposes. San Pedro is traditionally prepared as a tea or decoction and consumed as part of a healing or ceremonial ritual. It is believed to have a range of therapeutic effects, including promoting physical and emotional healing, increasing introspection and self-awareness, and facilitating spiritual growth. The mescaline in San Pedro is thought to act on serotonin receptors in the brain, which may help regulate mood and improve symptoms of depression, anxiety, and addiction.