The in vitro antimicrobial activities of crude ethanol, methanol and water extractsof the stem bark of O. gratissimumwere investigated. The extracts exhibited antimicrobial activities with zones of inhibition ranging from 10 to 20, 7 to 14 and2 to 7mm for methanol, ethanol and water extracts respectively. The minimuminhibitory concentration (MIC) of the methanol extract was between 0.5 and 10mgml-1 while that of ethanol extract ranged from 0.5 to 20 mgml-1,while MIC andMBC of streptomycin (Control strain) ranged between 0.065 and 0.5 mgml-1 forall tested bacteria. The minimum bactericidal concentration (MBC) for methanolextract ranged between 2.0 and 12.50 mgml-1, while that of ethanol ranged from2.0 to 20 mgml-1. Again all the extracts exhibited appreciable activity against allthe fungal species investigated. The zones of inhibition exhibited by the extractsagainst the test fungal species ranged between 2 and 9 for water, ethanol andmethanol extracts respectively. Phytochemical screening revealed the presence ofsaponin, steroids, tannins, glycosides, alkaloids and flavonoids in the extracts. Theability of the crude stem extracts of O. gratissimum to inhibit the growth ofbacteria is an indication of its broad spectrum antimicrobial potential which maybe employed in the management of microbial infections.