Phytochemical data are contrasted with phylogenetic relationships of carnivorous plants. Naphthoquinone profiles of a representative set of Nepenthes species are evaluated in comparison with previously published chemical data for Nepenthales (containing four distinct carnivorous plant families). The iridoids sarracenin and aucubin are identified as valuable chemical markers of Sarraceniaceae and Scrophulariales, respectively. The latter order (that contains the carnivorous Lentibulariaceae and Byblidaceae) is also characterized by the common occurrence of the phenylethanoid caffeic acid glycoside acteoside. No taxonomically relevant metabolite is known from Cephalotaceae so far.