Assessment of moluscicidal activity of the latex of three Euphorbia (Euphorbiaceae) species on Leptinaria unilamellata D'Obigny 1835 (GastropodaSubulinidae). Pulmonate terrestrial gastropods can be intermediate hosts for helminthes. The first records of chemically controlling these invertebrates date back to the beginning of the 20 th century. The substances used were unspecific toxins which were already used for controlling other pests. Synthetic molluscicides have technical limitations that stimulated a search for natural substitutes. Among the many vegetal species that have molluscicidal activity, Euphorbia cotinifolia L., Euphorbia milii des Moul. var. splendens (Bojer ex Hook) Ursch & Leandri and Euphorbia tirucalli L. call attention because of the excellent results that have been obtained when they are used on aquatic mollusks. However, studies on the activity of molluscicidal plants on terrestrial mollusks are rare, in spite of its great importance in controlling parasites and to agriculture. Anatomical and physiological similarities among species of aquatic and terrestrial mollusks suggest that chemical control strategies can be effective on both groups of invertebrates. Based on this hypothesis, we assessed the molluscicidal activity of the latex of three species of the genus Rev. Bras. Pl. Med., Botucatu, v.12, n.1, p.90-95, 2010.