Ethnobotany of Synandrospadix vermitoxicus (Araceae) in the Gran Chaco and neighbouring regions. Synandrospadix vermitoxicus is a native species of the Gran Chaco (Bolivia, Paraguay and Argentina) and neighbouring regions. An ethnobotanical investigation was conducted with the aim of summarising vernacular knowledge on the plant: common names, uses, its role in social and cultural life, as well as stressing the interest and value attached by human groups of the region. This paper is a summary of original data obtained in situ, in addition to those recorded in bibliographic sources. Oral information and herbarium material was collected during fieldwork carried out with eight ethnic groups, as well as with natives-criollos (local non-indigenous people) from Argentina and Paraguay. In order to contextualise the ethnobotanical information, brief references on the taxonomy, floristics, morphology, ecology, and phytonymy associated with this plant are added. Notes are also included on the plant’srole in different cultural settings: food, medicine, veterinary practice, magic, toxicology, mythology and witchcraft. Attention is drawn to the value of the plant for the ethnic peoples and settlers in the GranChaco and the interest it holds for them. The need to preserve it as natural and cultural heritage is also expressed.