Abstract: Preliminary investigations were carried out on the termiticidal potentials of aqueous extract of the leaf, fruit and bark of castor, Ricinus communis (Euphorbiaceae), on mortality and repellency of Macrotermes natalensis in the laboratory towards the development of alternative to synthetic termiticides. Ability of Nasutitermes species to rebuild broken termatarium treated with leaf and fruit extract was also investigated on the field. Results obtained show that the extracts had significant (p<0.05) effect on the test parameters. Symptomlogical response of M. natalensis to the extract included back lying of the insects prior to their death with overall reduced excitability. Highest response was observed in fruit extract. At 3 h after treatment (HAT), leave extract caused significant mortality. Between 6-12 HAT, mortality due to different extracts was not significant. However, at 24 HAT, mortality (82.00%) due to fruit extract was significantly higher than mortality due to other extracts. Also, fruit extract exerted highest repellency (90%) to M. natalensis, which was followed by 87.27% repellency due to leaf extract, both being class V repellency. The repellency due to bark (40%, class II) was significantly the lowest. On the field, both leaf and fruit extracts inactivated Nasutitermes species from rebuilding broken termatarium, whereas untreated control was rebuilt within 24 h.