Methomyl and the cardiac glycoside extract, isolated from Calotropis procera, were tested against the terrestrial helicid snail Eobania vermiculata (Müller) by the contact method. The LD₅₀ values of tested materials were 153.51 and 13.87 µg/ gm of body weight respectively, which means that the extract is 11 folds more toxic to this snail than methomyl. The spectrophototometric analysis of the cardenolide content of the tested extract proved that it is equivalent to 95 % ouabain, which is a good indication on the purity of the isolated group. At sub lethal doses of the tested extract, changes in alanine transaminases (ALT) level were higher than changes in aspartate transaminases (AST) levels. The results of this work proved that Calotropis procera is an important source for new and strong molluscicidal compounds that could be exploited against Eobania vermiculata and other species of harmful land snails.