Heartwood aqueous extracts from Enterolobium cyclocarpum (Jacq.) Griseb. exhibited chronic toxic lethal effect against Incisitermes marginipennis (Latreille) with more than 60% mortality at a concentration of 56.63 mg. Feeding rate correlated positively with the mortality of termites. The termite hindgut cellulolytic activity, the symbiotic microorganism population in termite hindgut and fungal cellulase activity were not inhibited by the aqueous extract. Two major chemical groups were detected in aqueous extract by gas chromatography; they were monoterpenes (46.5%) and phenols (18.7%). Fifty seven constituents, including, D-limonene, terpineol and eugenol were identified; these terpenes have repellent activity against insects. These results suggest that essential oils from E. cyclocarpum contain a slow acting toxin with a dissuasive effect on termites.