The chemical structure of compounds identified in species of the genus Zaluzania is reported herein, highlighting the contributions by Professor Pedro Joseph-Nathan to the chemistry of these plants. Although 36 names have been proposed for Zaluzania, only 14 species are currently accepted in the genus, and they are reported to be a rich source of sesquiterpene lactones and flavonoids. Their essential oils also contain several terpenoids, especially ent-kaurene-type diterpenes. In addition, we identified the guaianolides zaluzanin A and zaluzanin B, zaluzanin C, and zaluzanin D, and the eudesmanolides ivalin and ivalin acetate as the major constituents in infusions of aerial parts of Zaluzania augusta, Zaluzania parthenioides, and Zaluzania triloba, respectively. These sesquiterpene lactones were characterized by their physical and spectroscopic data, including 1H and 13C nuclear magnetic resonance (NMR). Likewise, the structures of zaluzanins C and ivalin were confirmed by X-ray diffraction analysis. The presence of guaianolides in Z. parthenioides and eudesmanolides in Z. triloba could be used as a biomarker to differentiate these 2 species, which were previously considered synonymous.