We documented harvesting, food preparation, and toxic risks of the poisonous chamal cycad, Dioon edule, in San Luis Potosi state, Mexico—one of a handful of places in Latin America where cycad eating persists. In Xi'iuy ethnic communities of the Pamería region, cycad consumption has long been intimately associated with cultural identity. The chamal food preparation process is protracted and difficult. Cooks seek to fully eliminate deadly toxins while achieving a pleasing taste and satisfying appearance in their cycad food products. Correct preparation is tested by a variety of methods difficult for amateur cooks to master. The complexity of the chamal culinary process, along with the ease of procuring foods more agreeable to the palate and less dangerous, out-migration of younger people, and preference for processed foods are some of the key factors that contribute to erosion of knowledge and use of this ancient wild food resource.