San Pedro – A cactus (Trichocereus pachanoi) indigenous to the northern Andes in South America, valued by indigenous doctors, curanderos, for inducing vomiting and visions. It is a common source of mescaline, which may account for its long popularity with “hallucinogen tourists” from North America.
SOURCE:
Historical Dictionary of Shamanism by Graham Harvey and Robert J. Wallis 2007