The Florentine Codex refers to the nanacatl and the teonanacatl (teunanacatl) as a "fever reducer" (in Anderson and Dibble's translation from the Nahuatl).
Sahagún, Bernardino de, Antonio Valeriano, Alonso Vegerano, Martín Jacobita, Pedro de San Buenaventura, Diego de Grado, Bonifacio Maximiliano, Mateo Severino, et al. Historia general de las cosas de Nueva España (Florentine Codex), Ms. Mediceo Palatino 218–20, Biblioteca Medicea Laurenziana, Florence, MiBACT, 1577. Available at Digital Florentine Codex/Códice Florentino Digital, edited by Kim N. Richter, Alicia Maria Houtrouw, Kevin Terraciano, Jeanette Peterson, Diana Magaloni, and Lisa Sousa, bk. 11, fol. 142v. Los Angeles: Getty Research Institute, 2023. https://florentinecodex.getty.edu/en/book/11/folio/142v . Accessed 20 November 2025.