The San Pedro cactus has a tradition among the Peruvian people as a tool for Shamans to heighten their awareness of a patient's illnesses. It has psychotrophic effects that would transport the healer to another place so they could receive instruction. It has been described as producing a feeling of tranquility and visions. The mescaline produces a transitory state that was used to help the healer find the answers to his questions so he could better help his patient. The cactus was also used in shamanic ritual as a religious artifact.
The San Pedro cactus has a role in Peru even today in health. It has been used traditionally to lower fever, treat kidneys and hepatitis. It is currently used to help battle alcoholism.
The juice of the stems is applied to wounds and scars to help heal them. It is also used to treat skin diseases such as dermatitis and dandruff.
The plant is also used in veterinary care as an anti-parasitic to remove pests in cattle and goats. The San Pedro cactus is also used to prevent foot and mouth disease in domesticated herds.
The mild-tasting fruit of San Pedro cactus can be eaten. The flesh of the cactus can also be eaten but the innermost part should be discarded as it contains the most alkaloids. The cactus can be dried and eaten as "cactus jerky" or eaten fresh like a cucumber. It is common in vegetable plates and South American and American Southwest cooking.
The cactus is also made into shampoo and laundry soap.