Many Verbenaceae contain one or more iridoid glycosides, several of which are still unidentified. Some of the latter were characterized by their specific optical rotations and RF-values on paper chromatograms. Iridoid glycosides were found in the tribes Viticeae and Clerodendreae (Viticoideae), Physopsideae (Chloanthoideae), Citharexyleae, Priveae, Lantaneae and Verbeneae (Verbenoideae) and Caryopterideae (Caryopteridoideae). In some of the subfamilies iridoid glycosides occur which are known from taxa of the Labiatae, viz. lamiide, ipolamiide, harpagide, acetylharpagide, and possibly some other glycosides. The prevalence and the distribution of iridoid glycosides in the Verbenaceae are in harmony with the propositions of Junell and of El-Gazzar and Watson on the delimitation of the Verbenaceae and the Labiatae, based on anatomical and morphological characters. They would, however, as well be in harmony with other delimitations.