Cactus San Pedro

While performing the ritual, sacrificers used different hallucinogens. The hieratic plant is cactus San Pedro, named after the saint San Pedro because he had the key to heaven. San Pedro is a subject in the Chavin art. Cactus San Pedro contains mescaline – alkaloid that causes optical and acoustic hallucinations. With its help the sacrificers would fall into a trance, transforming into a totem animal – jaguar, condor, snake, cayman, and when believed, it helped the sacrificers to contact the higher powers, learn the mysteries of being and possibly to influence the current of events. Delicate pipes made of birds' bones, which, according to archaeologists, were used to inhale drugs through the nose. Today's rituals are called Shamanism (Curanderismo) but now is for healing, good luck, love wishes, money and other economical and sentimental subjects.
Read more about San Pedro :
Wikipedia description
Ritual and archeologiccal evidences
Videos:
Current Shamanism

Legal information
Believers - Nat Geo
San Pedro - Flowers and seeds
Fake Shamanism