Commonly, false peyote refers to <i>Lophophora diffusa</i>. However, several other unrelated cacti go by this colloquial name. They either resemble "true" peyote, <i>Lophophora williamsii</i>, or are found in similar habitats. To date, over 40 different alkaloids have been isolated from the <i>Lophophora</i> genus. Of these, only the pharmacological actions of mescaline (<b>1</b>) have been extensively investigated. The major alkaloid in <i>L. diffusa</i> is pellotine (<b>2</b>), a tetrahydroisoquinoline (THIQ), which was briefly marketed as a sleeping aid around the beginning of the 20th century, following reports of its hypnotic properties in humans. Pharmacological experiments with the <i>Lophophora</i> THIQs were performed at the turn of the 20th century, whereas the chemical synthesis was not realized until several decades later. The biosynthetic pathways of the main <i>Lophophora</i> alkaloids were reported at the end of the 1960s. In this review, the relationship of the different "false peyotes" to <i>L. williamsii</i>, in regard to their alkaloid content, the bio- and chemical synthesis of the most relevant alkaloids, and their corresponding pharmacology will be outlined and discussed.