Mescaline is found in a range of cacti. It is the primary psychoactive alkaloid in these cacti, the most famous of which are San Pedro and Peyote. It can be given as a powder, capsules, or a brew. 

Mescaline has been used for millennia in Native American ceremonies. It is known to make the ordinary seem extraordinary and mystical. It may also lead to distortion of the environment and feelings from euphoria to increased connected thought and empathy.

Legal usage in the US is limited to the form of peyote and is only available to certain Native Americans.