This paper offers a historical perspective on the interactions between legal standards and agricultural practices relating to guaraná, an energy‐inducing Amazonian plant that is in increasing demand. Guaraná is managed in a number of socio‐technical contexts, ranging from the fizzy drink industry to alternative agro‐ecological farming systems, and is subject to a great many legal rules that determine the conditions for its use and appropriation. The paper shows how, in guaraná's native region of Maués, Brazilian Amazonia, various stakeholders including the indigenous population, associations of smallholdings and multinationals use legal standards in order to gain prerogatives over the plant and/or win a share of a growing market. In spite of the fact that the plant has been domesticated by the Sateré‐Mawé and that traditional knowledge has been recognized in Brazil, to a certain extent history has dispossessed them of their rights to guaraná. New political and economic circumstances have favoured those actors committed to strategies of agricultural modernization and industrial processing. On the other hand, the ecologization of agriculture and the increasing numbers of instruments for differentiating production (such as fair trade, organic farming and geographical indications) seem to be favouring diversification in the methods of managing guaraná, as well as a certain re‐appropriation of the plant by local communities.